Increasing complexity and diversity of management problems in modern enterprises requires the increasing diversity of models, methods, and methodologies. In creatively dealing with these complex, changeable and multidimensional management problems, i.e., problem situations, different systems methodologies for problem situations, structuring have been developed. Since no methodology is able to explore all aspects of the complex problems in enterprises, the topic of this paper is a multi-methodology approach that implies combining selected systems methodologies (Strategic Assumptions Surfacing and Testing, Team Syntegrity and Organizational Cybernetics) within a particular intervention. Therefore, research in the paper is relied on Critical Systems Thinking as a conceptual framework for combined use of systems methodologies. The paper aims to demonstrate how mixing the selected systems methodologies and tools can help managers in solving complex problems, such as the issues of strategy formulation and implementation in enterprises. Accordingly, combining these methodologies to support strategy formulation and implementation is applied to a Serbian enterprise.