The paper describes a model of protocol mechanisms for `integrating' resource reservations and multicast path setups. The protocol model is based on shared tree-structured channels in the network to which sources and destinations can connect to exchange data. The paper employs `flow aggregation' as a construct for realization of resource reservation protocols, as suggested by RSVP. Here, multiple flows that share a link in a tree are merged into a single equivalent flow for resource allocation purposes. Mechanisms to generate a composite flow from a set of flows and vice versa, constitute the functional elements of resource reservation protocols (e.g., bandwidth estimation for aggregated flows). These protocol elements can be parameterized with user-level flow specifications and topological placement of source and destination entities, for making resource allocation and path setup decisions. The novel idea is in casting the routing subsystems of multicast networks with RSVP-style resource, allocation functions.