EducaNext is an educational mediator created within the UNIVERSAL IST Project which supports both, the exchange of reusable educational materials based on open standards, as well as the collaboration of educators over the network in the realization of educational activities. The Isabel CSCW application is a group collaboration tool for the Internet supporting audience interconnection over the network, such as distributed classrooms, conferences or meetings. This paper describes the conclusions and feedback obtained from the integration of Isabel into EducaNext, it's use for the realization of collaborative educational activities involving distributed classrooms, lectures or workshops, as well as the general conclusions obtained about the integration of synchronous collaboration applications into educational mediators. Categories and Subject Descriptors H.4.3 [Communication Applications]: Computer conferencing, teleconferencing, and videoconferencing ? videoconferencing platform c...