A method is provided of authorizing a user of a communication system to be added to a group communication event. The method comprises: selecting a group of users of the communication system; initiating from a host node the group communication event with the group of users; responsive to receiving a group communication acceptance from at least a first user in the group, establishing the group communication event with the first user in the group; receiving at the host node a communication set up request from another user of the communication system; analyzing the communication set up request to determine if said communication set up request is associated with said group communication event initiated by the host node; and adding said other user to the group communication event if it is determined that the communication set up request is associated with said group communication event.