N.J. Stat. Ann. § 17:48E-25

The group contract may provide that the term "employee" shall include as employees of a single employer the employees of one or more subsidiary corporations and the employees, individual proprietors and partners of affiliated corporations, proprietorships and partnerships, if the business of the employer and those corporations, proprietorships or partnerships is under common control through stock ownership, contract or otherwise. The contract may provide that the term "employees" includes the individual proprietor or partners of an individual proprietorship or a partnership. The contract may provide that the term "employees" shall include retired employees. A contract issued to trustees may provide that the term "employees" shall include the trustees or their employees, or both, if their duties are principally connected with the trusteeship. A contract issued to the trustees of a fund established by the members of an association of employers may provide that the term "employees" shall include the employees of the association.