not quite.
what happens in a 'detected by' trigger is that, depending on who is looking out for who, flashpoint knows when they've been seen.
so for example, say you have a group of east loons (ai) patrolling an area, and there's a 'west detected by east' trigger over them. as soon as anything 'west' is detected within that area, flashpoint will know about it. what flashpoint does next is anyone's guess. usually the loons who have spotted the enemy automatically come running.
but say you have two groups of east loons, one in the north of a town and one in the south. the south loons could spot a westie and run after him, while the northern loons just keep on walking. very unrealistic. you can set up the waypoints for the second group so that if the westie is spotted by the first group, the second group come running too.