remove whats different between several audio tracks (cs6)

Hello. I would like to get the opening music from a bunch of videos that all have it. (specifically, the gameplay mechanics trailers and the aperture investment opportunity videos for the 2011 game, Portal 2)

my idea on how I would do that is to convert all those videos to audio and import that into audition cs6, then somehow remove the sound effects from the song by removing the difference between all the audio tracks.

I know how to convert to audio and import, but i dont know how i would do the difference-removal step.