(1) Disability insurance on a franchise plan is that issued to

(a) five or more employees of a common employer, or to

(b) ten or more members of any bona fide trade or professional association or labor union, which association or union was formed and exists for purposes other than that of obtaining insurance, and under which such employees or members, with or without their dependents, are issued individual policies which may vary as to amounts and kinds of coverage as applied for, under an arrangement whereby the premiums on the policies are to be paid to the insurer periodically by the employer, with or without payroll deductions, or by the association, or by some designated employee or officer of the association acting on behalf of the employer or association members.

(2) An insurer may charge different rates, provide different benefits, or employ different underwriting procedure for individuals insured under a franchise plan, if such rates, benefits, or procedures as used do not discriminate as between franchise plans, and do not discriminate unfairly as between individuals insured under franchise plans and individuals otherwise insured under similar policies.