No policy of group life insurance shall be delivered in this State unless it conforms to one of the following descriptions:
If none of the premium paid by the participating employer or labor union is to be derived from funds contributed by the insured persons specifically for the insurance, all eligible employees of that particular participating employer or labor union must be insured, or all except any as to whom evidence of insurability is not satisfactory to the insurer.
If part of the premium paid by the participating employer or labor union is to be derived from funds contributed by the insured persons specifically for their insurance, coverage may be placed in force on employees of a participating employer or on members of a participating labor union provided the group is structured on an actuarially sound basis.
N.C. Gen. Stat. § 58-58-135