Fluid Voice is a group communication platform that allows both real-time and asynchronous group activity participation. Users can form local audio broadcast networks for group discussion, similar to a conference call. Disconnected group members can be included in these discussions asynchronously: the audio is recorded and sent to them opportunistically. In this way, membership of a group persists in the face of disconnection caused by communication failures and mobility. Our platform supports other asynchronous applications: polling and voting, sharing of wish lists, and text messaging. We anticipate extending Fluid Voice to integrate messaging with environmental displays.