Collaboration in cooperative information systems, like concurrent design and engineering, exploits common work and information spaces. In this paper we introduce the TOGA service (Transaction-Oriented Group and Coordination Service for Data-Centric Applications), which offers group management facilities and a push model for change propagation w.r.t. shared data, thus allowing for group awareness. Through TOGA’s customizability and its layered architecture the service can be adapted to a variety of different collaboration scenarios. Multiple communication protocols (CORBA, UDP/IP, TCP/IP) are supported as well as basic transaction properties. Our approach enables both, firstly, the evolution of a set of separate applications to form a cooperative information system, i.e., it provides a technique towards component-oriented system engineering. Secondly, it can be exploited as a basic service within collaboration frameworks to effectively manage common work and information spaces. In this paper we report on design issues, implementation aspects, and first experiences gained with the TOGA prototype and its exploitation in an activity coordination and collaboration framework system.