Best way to manage music collection -- drag and drop?

We've got multiple Nexus 7's in our household (kids), and I'm having a hard time figuring out the best way to manage the different music collections of the different people. Many of the songs will be from CD's, from Amazon, from iTunes (DRM free) and new purchases on the Nexus 7.

It is a nightmare trying to manage it with different Chrome accounts on the same home computer -- because Music Manager is not suited for this. It won't let you identify certain folders for certain people. It treats the whole computer as the same for everbody.

I'm thinking of going to a "drag and drop" method for everybody. I'll just create folders for different people, then if I want a song on a device, hook the Nexus 7 via USB to the computer and drag and drop the song onto the device.

But will Google Music work like this? Am I going to have to switch the music app from Google Music (on a Google device, no less), just to avoid hassle in a multi-user, family environment?

 

The problem is that Google Music uploader does not handle switching users well. When I did a test, it re-scans and re-uploads everytime I switch it back.

So, if I sign in as Kid 1, and upload their "folder," then sign back in as myself, it re-uploaded from all the folders it had identified for me.

 

Looking again (after the weekend), it looks like Uploader didn't actually upload all the songs again -- it gave a status update while scanning that it was, but it apparently has the ability to overlook songs that were already there.

I wish it would give a more "comforting" notification to that effect. I don't want to create a bunch of ghosts and gremlins.

I think I'll set Google Music Uploader NOT to run automatically on start up. And so it will only run when I decide it's time for a session.

(This is made more complicated by the fact that I usually buy my music on Amazon).

 

This is basically the question I'm asking -- how best to do it.

It is one user per Nexus -- no problem there. But we share one computer at home. So the music collection is actually hosted on one hard drive, and we all have different music collections (or will). So the trouble is getting Google Music to easily manage which songs are in which connection -- I don't want it to try and sync each user with every song on that hard drive.

It's kind of a nuisance, frankly.