How can i hide a skeleton and set it so it still plays animations in third person?

So I have been working on a First Person Shooter and i have created a true fps view but for but for the sake of adding better aim down sights and reload animations I want to have a hidden mesh (only arm animations) that plays animations to the Full body mesh. But i can’t really find a way to implement this

For example: I want the First Person Arm Animations from the Shooter Game example to play in third person without the need of adding a new mesh.

Anyone know a way to do this?

Similar effect:

In this video the creator has hidden a FPP skeleton and made it so that it plays animation to the full body mesh thus making the reload animations and ADS animations