An embodiment is directed to an application server configured to set-up a communication session within a wireless communications system. The application server receives, from a session originator, a request to initiate the communication session with a set of session targets, and then transmits one or more call announcement messages for announcing the communication session to the set of session targets. The application server determines information associated with a probability that the set of session targets will fail to accept the announced communication session, and/or delay information associated with when call responses will arrive from the set of session targets in response to the one or more call announcement messages. The application server selectively grants a floor of the communication session to the session originator based on the determined information.