The aim of our work at Lancaster is to develop a distributed multimedia application platform. Such a platform must provide tools to enable programmers to construct distributed applications which make use of continuous media such as audio and video. If the platform is to be of use as part of a large scale distributed system, it must also take into account current standards activities such as ISO's Open Distributed Processing (ODP) standard without sacrificing the potential for high-performance necessary to support demanding media types such as high-resolution video [Blair,9l].Section 2 describes such a platform. As a result of a major applications survey and end-user study [Williams,91a], we decided to concentrate on providing support for building groupware style applications (in which groups of users interact). This decision to focus on groups has impacted on all areas of the platform. In section 3 we discuss our model of groups and explore its impact. Section 4 details our experiences of using such a platform, section 5 outlines our plans for future work and section 6 contains some concluding remarks.