Originally posted by Grailoch:

This gave me an interesting idea. I wonder if you could bring boss heads from another world in, hang them to access the buffs, but avoid getting any raids other than boar and neck.

Events are linked to the map you did the kill on. So hanging boss heads from other seeds does not change event status.

So if you have for example never killed a boss on 1 seed and put all 5 bosses heads up on that seed, you'll still just get the neck/boar event only.

And yes, you still access the buffs.