In the early 1950s the airport was served by the original Frontier Airlines (1950-1986) which flew DC-3's on a route from El Paso to Phoenix that included stops at Las Cruces, Deming, and Lordsburg, NM as well as Clifton, Safford, and Tucson, AZ.
A protected group is a group of people qualified for special protection by a law, policy, or similar authority. In the United States, the term is frequently used in connection with employees and employment.
The plain 'Members' list defines who belongs to the restricted group. Whilst the 'MemberOf' list, specifies which other groups the restricted group itself, belongs to. When you enforce a Restricted Groups policy, any current member that is not on the Members list is removed. Equally, any user on the Members list who is not currently a member of the restricted group is added to that group.