The supervisory control theory of discrete event dynamic systems was proposed in the framework of automata and formal languages. The concept of decentralized supervisory control was developed for the local supervisor S-i whose concurrent operation results in the closed-loop language L(boolean AND S-i/G) equal to that of global supervisor, L(S/G). In this letter we extend this concept by considering the problem of optimal combination of decentralized with centralized control in case pure decentralized control happens to be inadequate. We introduce the concept of locally controllable complementary tuple and present an analytical framework for nonhomogeneous decentralized supervisory control systems.