It's not in the GUI yet, only in the actual settings file for the character.
The reason it's not "officially" supported yet is because some bot logic needs to change for it to work correctly in more cases. The bot doesn't handle branching areas and knowing when it should not create a new instance or should very well yet. As a result, the bot can be sent into infinite loops during various scenarios of if it's trying to take a corrupted area transition in an area it needs to travel through to get to the grind zone. If you're in an area for too long and leave, the bot won't make a new instance either, which also messes up things when it tries to get back through.
