In a wide-area communication system, users or numbers in the system to be alerted are ranked so to improve the efficiency of the alert calls. Rankings are based on various factors, including whether two or more users are on the same active call, whether a user is on an active call, how recently a user ended a call, and whether a user recently missed a call. Within rankings, there may be multiple callers or numbers. These users may further be ranked, such as by determining which caller is expected to end a call first based on the current elapsed time of the call and the average call duration for that user or number.