Notwithstanding the retirement age requirements set forth in RSA 100-A:5, any member of the retirement system who has creditable service in both group I and group II, and who has attained the minimum age set forth in RSA 100-A:19-b, may retire on a service retirement allowance upon application as provided in RSA 100-A:5, I(a) or II(a). The split-benefit retirement allowance shall be determined as the sum of the retirement allowances with respect to service in each group classification computed as follows:
RSA 100-A:19-c
1988, 161:6, eff. July 1, 1988.