This paper proposes a novel formation control strategy for multiple nonholonomic mobile robots based on dynamic feedback linearization and supervisory control of discrete event systems. The proposed leader-follower formation strategy requires that all the robots navigate in an unstructured environment avoiding obstacles and following walls. In addition, the followers are also required to keep a predetermined geometric formation with the leader while relaxing some of the formation constraints in the face of obstacles. Considering the nonholonomic nature of the robots involved, we use nonlinear dynamic feedback linearization to develop a set of behavior based low-level controllers to achieve proper navigation of the system. And the higher-level discrete event system manages the dynamic interaction of the robots with the external environment. The use of discrete event systems reflects a modular manageable system with the potential for scalability and reusability. The proposed system is implemented through simulation and the results are shown to verify its operation.