Abstract: A multi-site trunked radio communication system (100) in accordance with a preferred method (500) assigns communication resources (117-124) in response to an assigned or requested service level. The service level is determined based upon a number of parameters (128) including affiliated communication site, time, user override service data, network override service data and other service mode assignment data. The parameters are used to dynamically generate and periodically update a subscriber unit service participation mode (SPM) for each subscriber unit (114-116) operating in the communication system. Additionally, an existing service participation mode assignment may be overridden by the user from the subscriber unit and/or by a network operator/manager.