Can you alter the default 3-4 racial songs it plays per level?

For example I am working on a human campaign, and by default it plays through the 3 human songs and the expansion pakc human song...
I want it to play through the 3 songs and NOT the expansion song, I want to save that track for the last level of my human campaign.

Have you tried : Campaign Editor --> Loading Screen --> Ambient Sound --> Game Sound ?

That has nothing to do with it at all.

Ok in sound editor search for the expansion human music and replace it with a sound of nothing simple as that u can make a unt sound wierd that way and replace music like in the night elf campaign when searching for tyrande(ihate her) and if furion's base is under attack its in a naga voice