Limiting a number of AI locations

In simple terms. There is one map. There is three actors that are AIs. One AI can enter the area of the other AIs, the other AI can enter its area and the area of the first AI mentioned. The last AI can only be in the area of the second AI.
Do you have tutorials that I could use. What would be a good set up to do this? How do I wire it up in Blueprints? Am I being unrealistic with the capabilities of Unreal Engine 4 and need to change my plan to something realistic?
I only want to know that someone has already done this.

not sure what the area is like

so why not add an tag on that actor and a box with collision set to overlap

whenever ai touches that box the box will see that if that actor has tag or not

if it haves it will run an function on it that will change its behavier tree to something else and in that behavier that ai goes somewhere away from its previous location.

i am not much of an expert in behavior trees but i did made something slimier once in which whenever ai saw player (pawn sensing) it ran other behavior in which it went towards player and after a delay , it went back to normal.

if you need more help just reply back in what.

cheers

You have given me a really good answer on using tags. I will do tests to see if a tag can do this and reopen the question is I get stuck. Thanks, I will look for my own guides.