A model is a simplified representation of an aspect of the world for a specific purpose. Complex systems typically give rise to more than one model because many aspects are to be handled. For software systems, the design process can be characterized as a (partially automated) weaving of these aspects into a detailed design model. While validation is usually feasible on each single aspect when it is the only one to be woven, validation is seldom possible on the complete detailed design resulting from the weaving of all the aspects. Hence we need weaving processes that exhibit good composition properties to allow multiple aspect weavings. We present an example of such a weaving process for behavioral models represented as scenarios.