Abstract. It is common that, in a long-term asynchronous collaborative activity, groups of users engage in occasional synchronous sessions. In this paper, we analyze the requirements for supporting this common work practice in typical collaborative activities and applications. This analysis shows that, for some applications, it is necessary to rely on different data sharing techniques in synchronous and asynchronous settings. We present a data management system that allows to integrate a synchronous session in the context of a long-term asynchronous interaction, using the suitable data sharing techniques in each setting. We exemplify the use of our system with two multi-synchronous applications.