(1) Under a group policy or contract issued to any common carrier or to any operator, owner, or lessee of a means of transportation, who or which shall be deemed the policyholder, covering a group defined as all persons or all persons of a class who may become passengers on such common carrier or such means of transportation;

(2) Under a group policy or contract issued to an employer, who shall be deemed the policyholder, covering all employees, dependents, or guests defined by reference to specified hazards incident to the activities or operations of the employer or any class of employees, dependents, or guests similarly defined;

(3) Under a group policy or contract issued to a school or other institution of learning, a camp, the sponsor of the institution of learning or camp, or to the head or principal thereof, who or which shall be deemed the policyholder, covering students or campers; and supervisors and employees may be included;

(4) Under a group policy or contract issued in the name of any religious, charitable, recreational, educational, or civic organization, which shall be deemed the policyholder, covering participants in activities sponsored by the organization;

(5) Under a group policy or contract issued to a sports team or sponsors thereof, which shall be deemed the policyholder, covering members, officials, and supervisors; or

(6) Under a group policy or contract issued to cover any other risk or class of risks which in the discretion of the Commissioner may be properly eligible for blanket accident and sickness insurance. The discretion of the Commissioner may be exercised on an individual risk basis or class of risks, or both.