Setting up AI to defend an area in scenario editor.

I have player 6, the AI, on a separate island on my scenario. I want them to stay in one place and not move, but when a player approaches them, they will move up towards the player and start attacking them.

I've tried going on this subreddit, the AOK forums, and the steam forums, but I haven't found a satisfactory answer so far. Setting the AI personality to none doesn't seem to work, using the stop unit trigger doesn't do anything, using the freeze unit trigger just makes everyone stand in place, but they don't respond to the player attacking them, and using the patrol to limit them to one area doesn't seem to work either. Is there another way to do this, or am I just using the triggers wrong?