Rob, not possible to do this any straight forward way.
Ideally, it should be as simple as copying folder(s) of loops to something like s Midi loop folder.

Note that I've mentioned folders, not files. This is simplest method to maintain / organise 3rd party stuff, as different companies tag content differently. It would be a mess to do this any other way. Even midi phrase giant Toontrack realized that, that is why their main library browsing is folder and not tag based.