Quote - Any way to "hide" or group these so they don't over-clutter the menus.

I would suggest this. Load a figure that only contains a BODY actor. If you don't know how to create such a figure, use "MinFig" from my free stuff.

Parent all the props to the BODY of the figure (if the props are already in a parenting chain, just parent the base of the chain to the BODY). Save the figure. Open the resulting cr2 in a text editor. Search & Replace the string "prop " (note the trailing space) with the string "actor " (note the trailing space). Save the cr2.

The collection of props has now been turned into a figure, though in many ways it still functions the same as when it was a collection of props. However, from the perspective of the 'Body Parts' menu, and technically, it is a figure.

The important point in practice is that none of the parts will show up in the Props menu. This fulfils your sated goal of not cluttering the Props drop-down menu. Instead, you access the parts by selecting the figure, then choosing from the  'Body Parts' menu of the figure. As far as the material room is concerned the actors are still props, and treated in exactly the same way as before.

If you used MinFig, and want to distribute the result, you should probably delete the material named "LesBentley", though this is only cosmetic, not compulsory.

The above represents a quick way to turn a bunch of props into a figure, and for your present purposes it is sufficient to the task at hand. However you should realise that in many ways it is not a normal figure. You can of course turn it into a normal figure if you want, but that involves more work.