Duh,
There's no other place to write them to really, or did you mean that I'm writing them to drawing objects and NOT the land of NOD?
If so, then yes, in XrefStates I wrote them to each blockTableRecord that was an xref. That way, AutoCAD handles the redundancy for me eg. when an xref is detached, the BTR is no longer there, so I don't have to update a master list somewhere else and possibly run the risk of having it get out of sync.
Make sense?