How to model bidirectional communication in Simulink?

Does anyone if it's possible to link two s-function blocks in such a way that they can send each other information? I've been trying to link the blocks directly, which implicitly creates a loop (connect A -> B and B -> A). The two blocks contain code defined finite state machines (FSM) with well defined transition between the states. However, when I link the blocks in a loop, Simulink fails to pass to the correct state (it stays way to long in a state). The states are discrete.

[SALAH alatai]

looking for something like that. if you have the solution please send it.