How to save audio files on my iphone, but not have them in my music?

I just bought Rosetta Stone and I want to put the audio files on my phone. However, there are more than 400 of them and I don't want them messing up my music. Is there anyway i can have them on my phone, but not appear in my music?

It's an iPhone 4s running iOS 8.0.2

I have EXACTLY the same setup as you. I dragged the folder of my Rosetta files OUT of the iTunes Media location, and parked it elsewhere, and do not sync or do anything that would cause my phone to every reinstall those files. I keep them on a separate mp3 player, and the folks are now accustomed to the strange lady who runs the track, muttering in Polish…