Multicasting of real-time streams (voice, video, etc.) for interactive communication in networked virtual environments (V.E.) is becoming an increasingly important service. Here as an example characteristics of interactive voice scenes for participants in a V.E. are presented. Proxy based overlay multicasting of real-time streams is a candidate architecture for this type of service. Here we propose a scheme for angular clustering of destination proxies in multi dimensional network geometric spaces as the core algorithm for construction of efficient overlay multicast trees. We show that using the proposed angular clustering scheme it is possible to construct source rooted overlay trees with acceptable delay and overhead traffic performances.