Group support systems impose specific requirements on the underlying infrastructure regarding communication, configuration and data management. In this paper we concentrate on computer-supported cooperative work in the area of software development. We present the main principles of an experimental toolset for cooperative software development, outline specific demands on the underlying infrastructure for such kinds of applications, and describe an object-oriented infrastructure that offers appropriate solutions for the identified requirements. The infrastructure is implemented as a suite of object-oriented frameworks. In addition to general services for distributed object-oriented applications, we offer services like group communication, configuration and object sharing that are especially useful for implementing group support systems.