This paper describes DOLPHIN, a fully group aware application designed to provide computer support for different types of meetings: face--to--face meetings with a large interactive electronic whiteboard with or without networked computers provided to the participants, extensions of these meetings with remote participants at their desktop computers connected via computer and audio/video networks and/ or participants in a second meeting room also provided with an electronic whiteboard and networked computers. DOLPHIN supports the creation and manipulation of informal structures (e.g. free hand drawings, handwritten scribbles) as well as formal structures (e.g. hypermedia documents with typed nodes and links) and their coexistence and transformation.