It would be awsome to have a sub linked parent/child group or groups within a main paernt child group.
Example...
Doors on a elevator style building (where the whole building is an elevator.
Here the door has to be linked to the elevator in order for it to function as an actual door regardless ov the buildings location.
Also spinning objects within a parent group. This would really be nice to have sub groups as its messy at times to link this correctly, without the whole thing spinning.