>>296690506
If I'm correctly understanding what you're asking, SteamVR Skeletal Input should be able to do that. You can supposedly get individual position and rotation data for all of the joints in each finger. It's just estimated if your tracking solution can't actually provide that information though, and I'm not sure which ones actually can. Valve claims you need "hi-end mocap systems, or gloves that measure the rotation of each finger segment" for full skeletal tracking.
https://github.com/ValveSoftware/openvr/wiki/SteamVR-Skeletal-Input
https://valvesoftware.github.io/steamvr_unity_plugin/articles/Skeleton-Input.html