Zeroing out Root Motion, is this valid approach?

Hello, I'm working on an animation where a Rider has to ride one Horse's back, and other similar Rider\Mount animations.

So, I need to animate both Rider and Mount. Then I need to zero-out world-space transformations of the Rider, so that it stays firmly attached to horse's back.

The easiest way to do it, is by moving root joint\control of the rider to the Mount's socket, animating this way, and then zeroing root out.

So the question is, can I do this in Unity?

I mean, I did this:
https://www.dropbox.com/s/gcvk6ngk30cj17y/SCR_09_Unity_AnimSetup_02_preview2.jpg?dl=0

And it works fine. But Bake Into Pose controls disappear if I select Root Motion Node, so the question is - is this valid? Or is it a bug and I should better zero out root animation in fbx file?