Library

Hello! I am a music producer, so I work with music samples a lot. Every time I seek for the right sample I listen through dozens of audio files and all of them are being automatically added to my apple music library which is synchronized with one on my iphone. So every time I want to listen my music in random mode I have to delete all these hundreds of samples that I don't want to appear in my random playlist from the library. My question is how do I forbid the adding of local audio files into my music library? Thanks