A system and method handles a group session of a communication group. The method includes determining server association data and access network association data for each mobile unit in a communication group. The server association data indicates a first association with a Push-To-Talk (PTT) server. The access network association data indicates a second association with an operating area respective to the PTT servers. The method includes determining a first MU of the MUs in the communication group being associated with a first PTT server and associated with a MBMS operating area of a second PTT server, the first PTT server controlling the group session. When none of the MUs participating in the group session is associated with the second PTT server, the method includes inviting the second PTT server to join the group session of the communication group.