Eligible volunteers, and all persons who subsequently become eligible volunteers, may apply to the Board for membership in the Fund. Upon becoming a member of the Fund, each eligible volunteer shall pay an amount to be set by the Board per quarter into the Fund. Each quarterly payment made by a member shall be supplemented by such contribution from the general fund of the state treasury for a period not to exceed 20 years as shall be determined by the Board and as may be appropriated by the general appropriation act. The quarterly payments shall be credited to the separate accounts of the members, and the matching contributions shall be credited to the Fund. The member contribution or any additional contribution to the Fund may be made by (i) the individual fire department or emergency medical services agency, provided it is paid for all eligible members of the Fund within the particular fire department or emergency medical services agency; (ii) local government, provided it is paid for all eligible members of the Fund who are volunteers for fire departments or emergency medical services agencies within the jurisdiction of the local government; or (iii) any other source provided it is paid for all eligible members of the Fund. Such accounts shall be kept so that they are available for payment on withdrawal from membership or upon receipt of the service award. No eligible volunteer shall maintain more than one membership in the Fund. In the event an eligible volunteer is in more than one eligible position, he must choose the position upon which his membership will be determined.