PrivTracker allows to share torrent files just with your friends, nobody else. Unlike public trackers, it shares peers only within a group which is using the same Announce URL. It really works like a private tracker, but can be generated with one click of a button.
I feel like if you need to keep a group of ten with synced files, there are already software solutions. And if the files are really large (updating a lot of servers) then you’ll be running your own private tracker anyways.