The design of complex systems involves various, possibly heterogeneous, structural and behavioral models. In model-driven engineering, the coordination of behavioral models to produce a single integrated model is necessary to provide support for validation and verification. Indeed, it allows system designers to understand and validate the global and emerging behavior of the system. However, the manual coordination of models is tedious and error-prone, and current approaches to automate the coordination are bound to a fixed set of coordination patterns. In this paper, we propose a Behavioral Coordination Operator Language (B-COOL) to reify coordination patterns between specific domains by using coordination operators between the Domain-Specific Modeling Languages used in these domains. Those operators are then used to automate the coordination of models conforming to these languages. We illustrate the use of B-COOL with the definition of coordination operators between timed finite state machines and activity diagrams.