Situational design methods provide problem solving guidance that can be configured to fit a range of different design goals and contexts. While the formal aspects of situational method engineering are well researched, the specification of method fragment instances and their configurations is often left open and regarded as specific to the respective design problem class. We propose an approach that analyzes variations of existing design solutions to explore the underlying design factors and to identify design situations. This knowledge is then used to derive method fragments and configuration rules that represent the explored variety of design solutions. The proposed approach has been applied for several design problem classes to construct concrete situational design methods. As an illustrative example, the construction of a situational design method for enterprise architecture management is used in this paper. Based on the exploration of eight design factors and three design situations, six method fragments are derived that are combined into four situational method configurations.