How to use Layered Blend Per Bone node in my scene?

Sorry to bother you there. I am using the Layered Blend Per Bone node in ue 5.3, and I found a problem I can not solved:
There I have two Anim Montage: the one will make left and rightarm move, while the another will only make leftarm move.
When I make the two poses into individual Blend Pose like the following:


I have tried but the result is not ideal:

  1. When I set Bone Name clavicle in Branch Setting, it can not do left arm movement when doing right arm Montage.
  2. When I set Bone Name spine, it caused the another Montage is invalid
    The ideal situation I want is that When I trigger rightarm Montage, the rightarm and leftarm will move; and when I trigger leftarm Montage, only the leftarm moves
    How to make correct Branch Settings? or is there other solutions? Every reply will be appreciated. :smile: