Bill,
It would seem that logically in Super Mode all engines should be associated with all/any TIUs set up in the remote.
Why would that seem "logical"?
DCS relies upon an engine being associated with only one TIU at a time. Super TIU mode is really a misnomer. It doesn't do anything to the TIU or the engine.
What Super TIU mode does is to tell a remote to send all commands for all engines to all TIUs, rather than only to the TIU with which the engine was last associated.
Add a name to the protocol between tiu and remote and everything is suddenly simple.
No, nothing is magically made "simple". Adding a "name" to a TIU is no additional way for a remote to identify it. A name would be redundant and serve no purpose.
Then the TIUs and Remotes were known by a (group/super) name like CLUB-A then they could ignore all messages to the wrong name.
OK, fine. Now, what if someone else were to name their "TIU Group" the same as your "CLUB-A"? Then,you're right back where you started from.
The relationship of the remote to the TIU to the DCS engines is at the very heart of DCS, and is most likely never going to be changed, unless and until DCS is completely rewritten. That's something that is, at best, several years away, if it happens at all.
Don't hold your breath. 
