The invention relates to a method for filtering and a network entity of the core network or the radio access network of a mobile communication system filtering streams belonging to a single user service. The packet streams, each being transported by a bearer service, provide a multicast or broadcast service and is delivered from a service center via the network entity to a mobile terminal. The network entity comprises a service manager providing a quality-of-service management function. The invention further relates to a communication system comprising the network entity. To provide an adaptive multimedia broadcast/multicast service QoS architecture that is scalable to a great number of users, the invention suggests providing the service in form of a packet streams, each being provided via a single bearer service, and equipping nodes within the distribution tree of the service filter capability allowing to (de)register bearer services providing the service based on the downlink quality-of-service constraints obtained from a service manager.