Red Thunder, has three music slots.
Name your files music end of battle music intro music splash
You can use the same piece of music for all three, or three different tunes, or two of one and one of another. Name your folder what you like, and then pop it into your "z" and it should work fine. Just an example ... CMRT West to East music
In my case I have one mod for when I am playing as the Russians, and one for when I am playing as the Germans, and just swap them in and out of my "z" folder.
The same format works for both Normandy/CW/MG and Italy. But Final Blitzkrieg only contains two music slots. Therefore your intro and splash music will be the same.