A way for the enemies to STOP chasing you?

[dre38w]

I first want to apologize if this was already posted and answered but I honestly have NO clue what to type in the search bar...
I have lots of enemies running around my levels and I need a way to have it so that the enemies chase the player only when in a certain radius. And then stop chasing the player once out of that certain radius. I am sure this all has to deal with scripts. If anyone knows of something let me know. I would greatly appreciate it.

 

[Mr_Smith]

You can use the XAS system for this, it has an enemy sensor that you can set, if you are out of the area the enemy starts wandering around the map, if you are in the sensor it sets to another path he takes and attacks you. I have, however, no idea if you can take this system out the XAS and use it for yourself.

 

[dre38w]

Okay kool. That raises a couple questions though...
What is the XAS System? And where do I find info on it?