Sharing external hard drive between mac and pc

Okay. I know this has been asked a million times, and yet I can't seem to find a straight answer.

Is it possible to safely, effectively, efficiently share an external hard drive with a traktor collection/various traktor files between a mac and pc?

I'm trying, and so far it works, sort of. My external hd is formatted exfat, and can read/write on both mac and pc. However, if I set my Traktor root directory to the external drive, some wonky stuff happens, on both machines. It's like the setting won't stick. When I close traktor, it wants to use the default file directory.

Next, there's the music. I've got a hefty collection of general mp3s, and I don't want ALL of them on this external "Traktor" drive. Just stuff that gets added to the Traktor collection. So, export collection, choose location, done. Until I get to the other machine. When I import the collection, it doesn't actually know where the files are, because Mac and PC use a different structure for drives ("D:" vs "Name"). Yes, I can relocate all of the files, but then... what happens when I go back to the other machine? Perhaps it's best to just export the collection from my desktop to the external drive, then copy the collection from the external drive to the laptop, and then relocate?

Maybe I'm just making this too hard. Ideally, I could sync traktor settings and collection between all three locations, but I'd settle for using the external drive as a backup/intermediary.

Thanks for your help!