Not sure I completely understand your question.
But when your troop triggers the manager, have it set a bool to true "in use". When the manager is done, on the last state, it can change itself back to false "in use".
When each troop tries to use the manager, have them check the bool first. If its true, then have them wait .1 second and try again. (No idea how long your manager takes). Then two troops cannot go through the manager at the same time, and will queue themselves.
Does that answer your question???