Except as provided by 19-2-403(4), an active member is not eligible to be covered under any other mandatory retirement plan to which an employer is required to contribute on the member's behalf while the member is eligible to be covered by this retirement system.
Ineligibility For Other Retirement Plans
Mont. Code Ann. § 19-13-302, under Eligibility, Membership, and Vesting.
Mont. Code Ann. § 19-13-302