This paper addresses the problem of rate and congestion control for video transmission in large multicast groups. A classification of the receivers is performed according to a predefined similarity measure (e.g. packet loss rate observed or TCP-friendly bandwidth share). The RTCP receiver reports are then filtered accordingly. The classification of receivers done by feedback aggregation agents helps in solving the feedback implosion problem in large multicast groups. The clustering and feedback aggregation mechanisms are coupled with an FGS layered video coding system in which the number of layers as well as their respective rates are adapted dynamically to aggregated feedback. The algorithm has been validated via NS 2 simulations.