(a) Any person who becomes a member after January 1, 1980, but before July 1, 1981, as a result of employment with a juvenile detention facility which has been acquired from a county by a state department and who was an employee of such county immediately prior to becoming a member of this retirement system in a position covered under its retirement or pension system shall have the option of transferring to the retirement system the employer and employee contributions credited to him for service as an employee of the juvenile detention facility. This option must be exercised within six months after becoming a member of the retirement system. It shall be exercised by notifying, in writing, the governing body of the county retirement or pension system and the board of trustees of the member's desire that such contributions be transferred.

(b) Within 30 days after receiving such notification, the governing body of the county retirement or pension system shall pay to the board of trustees of this retirement system an amount equal to such employer and employee contributions. Upon the receipt of such payment, the board of trustees shall deposit that portion representing employee contributions into the annuity savings fund as a credit to the member; and it shall deposit that portion representing employer contributions into the pension accumulation fund. Upon deposit of such contributions, the member shall receive credit for past service rendered as an employee of the county juvenile detention facility; but the amount of past service credited to such member shall be adjusted as necessary so that the accrued liability to this retirement system created by such past service shall be fully funded by the amount of the payment received by the board of trustees from the county retirement or pension system.

(c) If the payment received by the board of trustees is insufficient to cover all past service rendered as an employee of the county juvenile detention facility on a year-for-year basis, the governing authority of the county which formerly employed such member shall be authorized, but not required, to pay to the board of trustees an amount which, when combined with the payment of employer and employee contributions, shall be sufficient to fund all service rendered as an employee of the juvenile detention facility. In the event a county governing authority elects to pay such additional amount, it shall request, in writing, a certification from the board of trustees of such amount; and, upon such payment, the member shall be given credit for all service rendered as an employee of the county juvenile detention facility. The amount, if any, paid by a county governing authority shall be deposited by the board of trustees into the pension accumulation fund.

(d) In addition to persons who become members of this retirement system pursuant to subsection (a) of this Code section, the provisions of this Code section shall also apply to any persons who become members after July 1, 1986, but before December 31, 1987, as a result of employment with a county juvenile detention facility, the employees of which facility have been acquired from a county by a state department and who were employees of such county immediately prior to becoming members of this retirement system in positions covered under such county's retirement or pension system.