(a) As used in this Code section, the term:

(1) "Assistant district attorneys" means assistant district attorneys who are compensated from state funds pursuant to Code Section 15-18-14.

(2) "Prosecuting Attorneys' Council of the State of Georgia" means the Prosecuting Attorneys' Council of the State of Georgia created by Article 2 of Chapter 18 of Title 15.

(b) Each assistant district attorney and each employee of the Prosecuting Attorneys' Council of the State of Georgia, hereinafter in this Code section collectively referred to as "employee" or "employees," employed on June 30, 1979, may elect to become a member of the Employees' Retirement System of Georgia. Any such employee electing to become a member of the retirement system shall so notify the board of trustees not later than October 1, 1979. Any such employee who failed to notify the board of trustees by that date shall not at any time thereafter be eligible for membership in the retirement system. Any person who becomes an employee on or after July 1, 1979, shall become a member of the Employees' Retirement System of Georgia as a condition of his employment, unless he is eligible for membership in another publicly supported retirement or pension system or fund which provides retirement benefits based wholly or partially on compensation of such employee paid from state funds. An employee who is eligible for membership in any such other publicly supported retirement or pension system or fund may elect to become a member of the retirement system in lieu of membership in such other publicly supported retirement or pension system or fund by notifying the board of trustees of such election within 90 days after becoming employed with the Prosecuting Attorneys' Council of the State of Georgia. Any such employee who fails to notify the board of trustees within such time shall not at any time thereafter be eligible for membership in the retirement system. The state salary paid to employees who become members of the retirement system shall be the basis for employee and employer contributions for such employees. All employer contributions required by this chapter for such members shall be paid from funds appropriated or otherwise made available for the operation of the superior courts. The commissioner of administrative services shall deduct from the state salaries payable to such members the employee contributions required by this chapter.