CONFORMED COPY















                       GPA STOCK EXCHANGE AGREEMENT


                                between


 
                      GREEN SPRING HEALTH SERVICES, INC.


                                   and


                          CHARTER MEDICAL CORPORATION

                                  dated

                              November 14, 1995










                                                                CONFORMED COPY



                           GPA STOCK EXCHANGE AGREEMENT

           THIS GPA STOCK EXCHANGE AGREEMENT  ("Agreement") dated as of the 14th
day of November,  1995, is made and entered into by and between  Charter Medical
Corporation,   a  Delaware  corporation  ("Charter")  and  Green  Spring  Health
Services, Inc., a Delaware corporation ("GSHS");

           WHEREAS, Charter owns of record and beneficially all of the currently
outstanding  shares  of  common  stock of Group  Practice  Affiliates,  Inc.,  a
Delaware corporation and a wholly-owned subsidiary of Charter ("GPA"); and

           WHEREAS, GSHS wishes to acquire and Charter wishes to transfer all of
the GPA Common Stock in a  transaction  intended to qualify as a  reorganization
within the  meaning of Section  368(a)(1)(B)  of the Code (the  exchange of such
shares is referred to in this Agreement as the "GPA Stock Exchange");

           NOW THEREFORE, upon the terms and subject to the conditions set forth
in this  Agreement and the Stock  Purchase  Agreement (as defined  herein),  the
parties agree as follows:


                                   ARTICLE I.

                          TRANSFER OF STOCK; CLOSING

           Section 1. Number of Shares.  Charter  agrees to transfer to GSHS all
of the GPA Common Stock representing all of the issued and outstanding shares of
common  stock of GPA in exchange  for an  aggregate  of 969.04  shares of voting
common stock of GSHS, par value $0.01 per share,  to be issued at the Closing to
Charter.

           Section 2.  Transfer and Delivery of the GPA Common Stock and the New
GSHS  Shares.  At the GPA  Closing,  Charter  shall sell,  assign,  transfer and
deliver to GSHS all of the GPA Common Stock by delivery to GSHS of a certificate
or certificates  representing  such GPA Common Stock, duly endorsed for transfer
or  accompanied  by duly  executed  stock  powers.  As provided for in the Stock
Purchase  Agreement,  GSHS  shall,  immediately  upon  the GPA  Closing  and the
Closing, issue to Charter a certificate or certificates, in the name of Charter,
representing the GSHS Shares and the New GSHS Shares.

           Section 3.        Time and Place of Closing.  The closing (the "GPA 
Closing") of the GPA Stock Exchange will be held at the same time and place as 
the Closing.


                                ARTICLE II.

                                TERMINATION

           Section 1.        Termination.  This Agreement may be terminated at 
any time prior to the GPA Closing by either party to this Agreement upon the 
termination of the Stock Purchase Agreement.

           Section  2.  Procedure  and  Effect of  Termination.  In the event of
termination of this Agreement  pursuant to Section 1 of this Article II, written
notice of such termination  shall promptly be given by the terminating  party to
the other party,  and this Agreement shall upon that notice terminate and become
void and have no effect,  and the  transactions  contemplated  by this Agreement
shall be  abandoned  without  further  action by the  parties,  except  that the
provisions  of the  Confidentiality  Agreement  and  Section  11.5 of the  Stock
Purchase Agreement shall survive the







termination of this Agreement,  provided,  however,  that such termination shall
not relieve any party of any liability for any breach by it of this Agreement.


                            ARTICLE III.

                           MISCELLANEOUS

           Section 1. Stock Purchase  Agreement.  Capitalized terms used but not
otherwise defined in this Agreement shall have the definitions  ascribed to such
terms in that  certain  Stock  Purchase  Agreement,  dated as of the 14th day of
November,  1995, by and among Blue Cross and Blue Shield of New Jersey,  Inc., a
New Jersey  health  service  corporation,  Health Care Service  Corporation,  an
Illinois legal mutual reserve company,  Independence  Blue Cross, a Pennsylvania
non-profit   hospital  plan   corporation,   Medical   Service   Association  of
Pennsylvania, a Pennsylvania corporation,  Pierce County Medical Bureau, Inc., a
Washington  non-profit  corporation,  Veritus,  Inc., a Pennsylvania  non-profit
corporation, GSHS and Charter.

           Section 2.  Counterparts.  This  Agreement  may be executed in two or
more counterparts,  all of which shall be considered one and the same agreement,
and shall become  effective  when one or more  counterparts  have been signed by
each of the parties and delivered to the other party.

           Section 3.  Governing  Law. This  Agreement  shall be governed by and
construed in accordance  with the laws of the State of Delaware  applicable to a
contract executed and performed in such state without reference to the choice of
law principles of such state.

           Section 4. No Third Party Beneficiaries. Nothing in this Agreement is
intended,  nor shall it be construed,  to confer any rights or benefits upon any
Person  (including,  but not limited to, any employee or former employee of GSHS
or any Subsidiary) other than Charter and GSHS (and their successors and assigns
to the extent  specifically  permitted  by Section 7 of this Article III) and no
other  Person not a party to this  Agreement  shall have any rights or  remedies
under this  Agreement,  except for  Persons  entitled to  indemnification  under
Article 9 of the Stock Purchase Agreement (and such rights and remedies shall be
limited solely to those provided by Article 9 of the Stock Purchase Agreement).

           Section 5. Entire  Agreement.  This Agreement,  the Buyer  Disclosure
Schedule,  the GPA Disclosure Letter, the GSHS Disclosure  Schedule,  the Seller
Disclosure  Schedule,  the Exchange Agreement,  the Stock Purchase Agreement and
the New Stockholders' Agreement contain the entire agreement between the parties
with respect to the subject matters of this Agreement and such other agreements,
and  such  agreements  supersede  all  prior  and  contemporaneous   agreements,
representations, negotiations, discussions, correspondence, communications, term
sheets  and  understandings  of the  parties,  except  for  the  Confidentiality
Agreement,  which  agreement  is ratified  and remains in full force and effect.
There are no agreements, understandings,  representations and warranties between
the parties other than those set forth or referred to in this Agreement and such
specifically listed above other agreements.

           Section  6.  Notices.  All  notices  under  this  Agreement  shall be
sufficiently  given for all purposes under this Agreement if in writing (a) when
delivered personally; (b) three Business Days after mailing in the United States
Postal  Service;  (c) one day after  sending by  documented  overnight  delivery
service;  or (d) when  receipt  is  confirmed,  by  telecopy,  telefax  or other
electronic  transmission  service  to the  appropriate  address or number as set
forth below.
Notices to GSHS shall be addressed to:

                    Green Spring Health Services, Inc.
                    Clark Building, Suite 500
                    5565 Sterret Place
                    Columbia, Maryland  21044-2642
                    Attention:  Joyce N. Fitch, Esq.
                    Telecopier: (410) 740-2686






                                                                 CONFORMED COPY

           with a copy to:

                    Venable, Baetjer and Howard, LLP
                    1800 Mercantile Bank and Trust Building
                    Two Hopkins Plaza
                    Baltimore, Maryland 21201
                    Attention:  Alan D. Yarbro, Esq.
                    Telecopier: (410) 244-7742

or at such  other  address  and to the  attention  of such  other  person as may
designate by written  notice to Charter.  Notices to Charter  shall be addressed
to:

                    Charter Medical Corporation
                    Suite 1400
                    3414 Peachtree Road, N.E.
                    Atlanta, Georgia  30326
                    Attention:  Michael Catalano
                    Telecopier: (404) 814-5797

           with copies to:

                    Charter Medical Corporation
                    3414 Peachtree Road, N.E.
                    Atlanta, Georgia  30326
                    Attention:  Cherie M. Fuzzell, Esq.
                    Telecopier: (404) 814-5795

                    and

                    King & Spalding
                    191 Peachtree Street
                    Atlanta, Georgia  30303
                    Attention:  Robert W. Miller, Esq.
                    Telecopier: (404) 572-5144

or to such other  address and to the  attention  of such other person as Charter
may designate by written notice to GSHS.

           Section 7.  Successors and Assigns.  This Agreement  shall be binding
upon and  inure to the  benefit  of the  parties  to this  Agreement  and  their
respective successors and permitted assigns;  provided,  however, except for the
right of Charter to grant to or for the benefit of the lenders  under the Credit
Agreement a security interest in its rights under this Agreement pursuant to the
Credit Agreement and the documents from time to time securing the same,  neither
party to this  Agreement  shall have the right to assign its rights or interests
in or delegate its  obligations  under this Agreement  without the express prior
written consent of the other party to this Agreement.

           Section 8. Amendments and Waivers. This Agreement may not be modified
or amended except by an instrument or instruments in writing signed by the party
against whom  enforcement of any such  modification or amendment is sought.  Any
party to this Agreement may, only by an instrument in writing,  waive compliance
by the  other  party  to this  Agreement  with  any  term or  provision  of this
Agreement.  The waiver by any party to this Agreement of a breach of any term or
provision of this Agreement shall not be construed as a waiver of any subsequent
breach.








           IN WITNESS WHEREOF, this Agreement has been signed by or on behalf of
each of the parties as of the date first above written.

                                 CHARTER MEDICAL CORPORATION


                                 By:    /s/ E. M. Crawford
                                       ----------------------------------------
                                    Title: Chief Executive Officer


                                 GREEN SPRING HEALTH SERVICES, INC.


                                 By:   /s/ Henry Harbin
                                      -----------------------------------------
                                    Title:President and Chief Executive Officer