How can I active only some of enemies?

Hello !
I am very beginner in this and for now I can open door and activate gravity with delay for object so pls be patient.
I have idea for small project or at least i think so. Its simple you are guy who runrs around looking for exit while around you spawn enemies which chase you when they see you and I have found tutorials which will satisfy this (or at least I think so)
But I want tiny twist.
I want them spawn as “inactive” and only start chase and search when in some proximity to player (or been seen by player) but some just never wake up just be there standing so player will never know if this one will chase him.
I suppose I will have to build some sort of list and before activating any sort of AI I will have to check if this one is active one or no am I right?
I use blueprints and I am still pretty lost.
Thanks.