1.  No insurer or person on behalf of any insurer shall offer, make or permit any preference or distinction for purposes of any property, casualty or, surety insurance coverage, as to form of policy, certificate, premium, rates, benefits or conditions of insurance, whether by master policy, individual policies, certificates of insurance or by any other means, based upon membership, nonmembership, or employment of any person or persons in or by, any group, association, corporation, organization or other combination of persons, based upon marketing through groups, associations, corporations, organizations or other combination of persons, or based upon a group or mass merchandising program of any kind; and shall not make any such preference or distinction available in any event based upon any fictitious grouping of persons. For the purposes of this section a fictitious grouping is defined as any grouping by other than a common insurable interest as to the subject of the insurance and the risk to be insured.  

2.  This section shall not apply as to any grouping placed in effect prior to January 1, 1968.