Sec. 3.1. For a member who receives annual compensation from two (2) or more employers, the average of the annual compensation shall be computed using the sum of the two (2) or more annual compensations if:
(1) each of the employers and the member made all of the contributions required by IC 5-10.2; and
(2) the member occupied at least one (1) position that normally required performance of service of more than six hundred (600) hours during the year.