1. A method for providing multi-party voice-over-IP services, the method on an information processing system comprising: establishing a peer-to-peer distribution tree to broadcast a composite audio signal from a root mixing node to a plurality of participating nodes, wherein a subset of the participating nodes are originating nodes that provide a respective audio stream output received by the root mixing node to produce the composite audio signal; and identifying, independently of the peer-to-peer distribution tree, a first intermediate mixing node from within the plurality of participating nodes, the first intermediate mixing node providing to the root mixing node a mixing of respective audio stream outputs provided by a first subset of originating nodes to the first intermediate mixing node.