I'm still not very clear about your request.
Bridge can add labels and ratings to any file formats (include folders and XMP-unsupported files). The labels and ratings value will be recorded into a hidden file (named .BridgeLablesAndRatings) that in the same location of the folders and XMP-unsupported files. The file is also hidden in Windows or Mac OS. If you try to move/copy the labeled/rated folders or XMP-unsupported files in Bridge, the labels and ratings will be moved/copied to the corresponding hidden file in the new location automatically. While if you try to move/copy the folders or XMP-unsupported files in Explorer of Finder, the labels or ratings will lost.
Do you think the exist label feature in Bridge can solve your problem? Or I misunderstood your meaning?
Adobe Bridge QE