AI - Surround Player

Hey Unreal Com!
My NPC Enemys currently have a pretty basic Behavior Tree:
Is Enemy close to Player?
Yes: Attack him
No: Move To Player

This ends like in the photo I added. Some of them stack up, and cant attack the player.

It would be awesome if you can give me a hint on how to surround the player, like in warcraft 3.
Maybe find locations with an eqs and then check if their already is someone?

Thanks in advance and have a nice weekend.