How to use RigidBody node to "simulate" physics on skeletal mesh attached to virtual bone?

I have a character mesh with a virtual bone (VB Sword) that I have attached another skeletal mesh to. (A...sword.....imagine that).

The sword's skeletal mesh has a root bone (Sword) with several other bones, that help drive some physics constraints that should make the dangly bits swing and sway.

Now, obviously, setting the attached bone on the skeletal mesh's detail's means there cannot be any physics, but I think there is a way to do this using the rigid body node in the animation BP of the character's blueprint, but am sort of confused on anything more than that, w/re to setup. (do I need to modify the base skeleton to have additional bones? or ... what?)