In determining the municipal employees entitled to participate in the system and the extent of their participation, all service performed by an employee in the employ of any municipality which joins the system, for such employer, shall be included except as provided in this section. The following services shall be excluded: (1) Services which, in the absence of federal-state agreement, would constitute “employment” as defined in the Social Security Act, (2) services of individuals in positions covered under the Connecticut State Teachers’ Retirement Association other than services performed by individuals to whom Section 218(c)(3)(B) of the Social Security Act is applicable; services performed prior to August 16, 1994, of individuals in police officers’ or firefighters’ positions covered under fund A or fund B or local retirement systems, and (3) services which, under the Social Security Act, may not be included in an agreement between the state and the Secretary entered into under sections 7-452 to 7-459, inclusive. Service which under the Social Security Act may be included in an agreement only upon certification by the Governor in accordance with Section 218(d) of said act shall be included if and when the Governor issues, with respect to such service, a certificate to the Secretary pursuant to section 7-455. Any municipality applying for membership in the system may elect to exclude from membership in the system the following: (a) All services in any class or classes of elective positions, part-time positions or positions the compensation for which is on a fee basis, (b) student service to the fullest extent such coverage is permitted under Section 218 of the Social Security Act, (c) services performed by individuals to whom Section 218(c)(3) (B) of the Social Security Act is applicable, or (d) any services which may be optionally excluded under Section 218(c) of the Social Security Act. Any municipality which joined the system prior to July 8, 1955, shall be deemed to have elected exclusion (c). Where any municipality covers under the agreement the services described in exclusion (c), the services of any individual thereby covered shall cease to be covered by the agreement if he thereafter becomes eligible to be a member of a retirement plan, but only if the agreement is not already applicable to such plan pursuant to Section 218(d) of the Social Security Act. Nothing in sections 7-451 to 7-459, inclusive, shall prevent coverage under the system in accordance with Section 218(d)(8) of the Social Security Act of services of individuals in positions covered by more than one retirement system. Where, prior to June 29, 1959, services in positions covered by a retirement system have been covered under the system, the legislative body of a municipality may request that services of individuals excluded from such coverage because such positions were covered by another retirement system be included under the system, and such services shall be covered under the system in accordance with Section 218(d)(8) of the Social Security Act.