Well, that scratches my previous project. I think this will work out much better than waiting for the Tethered adapter from MTH.
My original tether box ran into issues with translating the TIU ID to the proper device. I eventually had to program all of the receiver boxes to recognize TIU ID 1 and then set the remotes to speed mode to ignore return messages. This solved most of the problems but I digress, what has been developed by Mark is what MTH should have done from the get go.