Impact Layers Problem

[atmuc]

I have AI characters. They attack player with a melee weapon. AI characters are in Enemy Layers, the player is in Character layer. I set melee weapon Impact Layers as Character checked, Enemy unchecked. When AI character group starts to hit the player they kill each other. The last enemy kills the player. How can I stop Enemy damages Enemy?

 

[atmuc]

I found the problem. I cleared all layers from the layer mask except Enemy. I think something changes the layer of the rig to SubCharacter.