PivotPaint equivalent for ProBuilder?

Hey so in Unreal there's this tool called the PivotPainter which lets you store submesh pivot's into an extra UV channel on the model. https://docs.unrealengine.com/en-us/Engine/Content/Tools/PivotPainter

Storing the submesh pivots in the extra UV channel, in turn makes them available to vertex shaders to do stuff people might otherwise try to use expensive skeletal animations for. This is the technique used in Fortnite's build shader like you can see in this GDC talk. https://www.gdcvault.com/play/1017699/The-Inner-Workings-of-Fortnite

I am new to ProBuilder and trying to figure out if there's a way to store data like that in the extra UV channels of a submesh of an object that I create. Possibly by first creating my object as a bunch of separate ProBuilder objects and then doing a static assignment of the extra UV data on each of them before doing a merge into single object as the final operation. Can anyone point me to any tutorials or anything that might cover such a use case?

 

https://github.com/slipster216/VertexPaint this seems to have something like it (haven't used it, just rediscovered that recently)