You can put something distinctive on you luggage that will make it different from the others. You need to think of something that is easy to recognize, but that other people may not be using. My last trip through the airport, about half the bags had curly ribbon on the handles, and everyone had to check the tags anyways. A lot of people do something cute like ribbon, or little dolls, etc. But when everyone is doing the same thing, it just doesn't help.
I went a different direction; I put something ugly on the handle, black and yellow industrial rope, spliced around the handle and melted so it can't come off. I always know which luggage is mine, it's not big enough to look too ugly, but you can see it as soon as it comes out. Try to think of something you like, and can easily recognize; somethinig sturdy enough so that it won't fall off, but doesn't get in the way.
As to how to keep them together for when they come off, I couldn't begin to guess.