Abstract: A bridging system comprises a router and a number of multipoint servers. For each user requesting to join a particular conference, the router routes the call to a particular server and, if necessary, causes additional servers to be added to increase the capacity for that conference. For example, upon receipt of a user request to join a conference associated with server A, the router first interrogates server A as to current spare capacity. If server A has additional capacity, the router routes the user to server A. However, if server A can not accommodate the user, the router causes server A to invite an additional server—server B—to join the conference. After server B joins the conference, the router routes the user to server B.