Is there a plugin or way to a have npcs at monuments pull other npcs within a proximity to aggro against a player when said player attacks an npcs?

For example, if there are 3 npcs close to each other and a player shoots one, I want the other 2 close by to also notice and start attacking the player. For now, the other npcs will just stand there while their buddy is getting shot and shooting back.

No plugin that i know of, all the ones i have used behave the same way.