(1) A corporate credit union must be operated primarily for the purpose of serving other credit unions. (2) Membership in a corporate credit union must include credit unions organized and operating under this chapter or under any other credit union law. (3) Membership may also include: (a) officers, directors, committee members, and employees of credit unions; or (b) organizations and associations of those persons or organizations enumerated in subsections (2) and (3)(a). (4) The membership of a corporate credit union may not include more than seven natural persons as described in subsection (3)(a).