Would be great for mixing partial songs together fast, as well as making routing/dsp-chain systems reusable.
The simplest starting point for this feature would be to extend track clipboard functionality to groups. If it carries pattern data and used instruments along with it, all the better.
Sooo many partial songs and bits I need to recycle. Too scared to do it at the moment! 
Sounds like something someone could script, no?
I suggested something similiar some days ago. Having a new point named “group” or “template” next to “song, instrument, sample” in the file selector would be cool stuff 
+1
I’d like to see just dragging in an XRNS straight-up. Reason being, you don’t want to force the user to have to convert all their XRNS to group/template files. Just use XRNS as the group export format.