Hi Greg,
(I don't want to worry you, but...) I think what you're planning is very unlikely to work without development. The standard code for determining the RFC destination of the GTS system expects to find exactly ONE target.
Some of the transactional code includes a BAdI where you can specify alternative determination of the RFC destination, but the Master Data modules do not. You will need to enhance or re-write the distribution Function Modules.
GTS 10.1 contains all of the functionality of GTS 8.0, so I would suggest that it would be easier to use a little BAdI code to filter out the reluctant business unit for the new functionality than to go the way you describe. Of course, I'm saying that without knowing anything about the planned functionality!
Regards,
Dave