Any employee of the State of Nebraska, of any political subdivision thereof, of any municipal corporation, or of any public body or agency created by the laws of this state, who desires to participate, voluntarily, in a plan of insurance, designed and intended for the benefit of a specific group of public employees, participation in which is restricted to the employees of a specific agency, public body, municipal corporation, political subdivision of the state, or any department of the state, may execute an order, authorizing the withholding from any wages or salary paid to such employee of a sum each month which is equivalent in amount to the sum fixed by an insurance carrier as the monthly premium to be paid by the employee for participation in such group, franchise, or wholesale plan of insurance, or a sum, each month, which is equivalent in amount to the sum fixed by an employees association which association may be the policyholder and premium payer of such group, franchise, or wholesale plan of insurance.