I don't know about current versions of I-tunes, but on older versions you can turn off I-Tunes having control over your original music folders. That way, it doesn't make copies of anything. It has to go to your original one and only copy to play it.
I have no idea if you can do that in current I-Tunes or if you have some over-riding reason why you need multiple copies.
The control to turn that off is in the options or preferences menu.