The main focus of this paper is demonstrating a methodology for capturing and designing co-operative work processes. We present a method, appropriate for group work analysis, and particularly well suited for the analysis and design of workflow applications. With this end in view, we have chosen the OSSAD method as a foundation for a specific method for co-operative applications analysis and design. We propose several improvements which consist in an organisational dimension to the models, and an information flow diagram. Within this framework, we propose the use of group-oriented models to describe steps of co-operative work which cannot be represented using a workflow model.