Basically, yes. It doesn't have to be a hold waypoint though, that's just a good one because it makes the loons behave in the right way while they are waiting. A group will wait at any waypoint synched to a switch trigger until the trigger is fired, at which point they will proceed to the next one. They will also proceed directly to the next one even if they haven't reached the synched trigger yet.
For example, if you have a patrol with a bunch of move wps, a cycle and a seek and destroy with the cycle synched to a switch trigger, when the trigger is fired they will move immediately to S&K, missing out all the remaining move wps.