A Wisconsin retirement system is created, including the benefits provided by this subchapter, the disability annuities provided by s. 40.63 and the death benefits provided by ss. 40.71 and 40.73. For purposes of determining an employee’s eligibility for social security coverage only, the former state teachers retirement system and Milwaukee teachers retirement fund and the local police and fire pension funds established under s. 61.65 (1), (6) and (7), 1975 stats., and s. 62.13 (9) (e), (9a) and (10)
(f) and (g), 1975 stats., shall continue to be considered separate retirement systems but for all other purposes the Wisconsin retirement system is a continuation of the Wisconsin retirement fund.