Except as provided in Code Section 47-2-265, each full-time employee of a district attorney, which employee is compensated through funds appropriated by the General Assembly, shall be a member of this retirement system as a condition of employment. Any such employee who is already a member of this retirement system by virtue of service with another employer shall be entitled to credit for all service rendered while an employee under the retirement system. All contributions required under this chapter shall be paid from funds appropriated or otherwise available for the operation of the superior courts. The Department of Administrative Services shall deduct from the state salaries paid to such members the employee contributions required by this chapter.