A benevolent society may provide for the classification of its membership by one or more units based on the age of individual members, or by the adoption of a maximum limit of one group or unit. Before the organization of a new group or unit, the society shall notify the commissioner of its proposal to organize the group or unit, and the organization must be conducted in accordance with any applicable rules adopted by the commissioner. The number of members in a unit may not be less than is required for the organization of a society. If the membership of any group or unit of any society falls below two hundred, the group or unit must be consolidated with another group or unit of the society unless within sixty days the group or unit has restored its membership to the minimum required by this section. An age group composed of members over age sixty-five, however, may be established and maintained at not less than one hundred members.