A system includes an event notification system coupled to a communication network element and to a subscription database. In response to a subscribe message for a party received from the communication network element, the event notification system determines at least one service from a plurality of services for the party from the subscription database, sends a service subscribe message to a device associated with a service for each service of the at least one service, determines a notification value for the party based on service pushed values received in response to each sent service subscribe message, and sends the notification value to the communication network element. The notification value is used by the communication network element to determine whether to invoke an internet protocol multimedia subsystem service for an incoming call to a communication address associated with the party.