I suppose keeping the full menu structure isn't absolutely necessary. Normally, in most cases I just use BDRB and import the segments and use it's own menu. It's just that in this case, there are quite a few Xtras, so it would be CONVENIENT to be able to keep the menu structure if possible. I know JD is rolling his eyes right about now saying, 'Just compress the whole disc already!'
That's probably what I will do. Just would have been interesting to figure out how to do it.