if the action is in a trigger make a hold waypoint for the helicopter where you want it to wait.. give it another where you want it to go etc..
in the trigger that activates the chopper change the Type: from none to Switch and then click on Syncronize in the top of the screen
click on the hold waypoint and drag the mouse over onto the trigger.. now let go and a blue line should run from the waypoint "HOLD" to the trigger.. now the trigger since its set to switch switches the waypoint to the next waypoint in the list when the trigger activates.. the chopper will now fly to the next waypoint and so on etc...