How to choose which animation to blend?


I have a character with a blend space for basic animation working. He walks/run and idles.
I also have two animations that I would like to blend with this working blend space.

First animation is a single frame animation which he is holding a box with two hands.

The second animation, my character is swinging a sword with his right hand.

I know that I can use the Blend per bone node to blend one of the animations with the blend space using a bone as a “filter”, So the blend will start from that bone.

The animation when he is hold a box, would start on his spine, but the animation hold a sword, would start on his arm bone.

I tried to setup the Blend per bone node using these bones as filters for each Pin, but the result is wrong. I guess its because the layered base system. (priorities)

Question is: Should I create a different montage for each animation that i need to blend with my blend space? I tried having only one montage with all animations on it, but i failed.