A controller 103 in a communications system (FIG. 1) for controlling communications with a group 125 of associated subscriber units and method thereof, where the controller includes a receiver (part of 603) operable to receive a request for a subscriber unit to communicate with the group of associated subscriber units; and a processor 605 coupled to the receiver and operable as a comparator 619 to provide a comparison of a first association constraint (FIG. 3) corresponding to the subscriber unit and a second association constraint (FIG. 4) corresponding to the group; and a decision function 621 that allows, only when the comparison is favorable, communications between the subscriber unit and any other subscribers of the group of associated subscribers that also have such communications allowed or enabled.