I've got a simple dynamic working when AI objects shoot at the player objects. The player can potential have more than one object so I've grouped all player characters into a family called "minions".
My problem comes when a bullet hits a minion. The event is
Bullet On Collision With Minions > Minions subtract bullet.damage from health.
The only problem is that when a bullet hits a minion it subtracts health from all minions on the map. I could create a event for the bullet colliding with each minion but that seems wasteful and not very efficient.