Volume Levelling Multiple Files in Multitrack

Hi All,

I hope it's ok to ask here? I have a .sesx multitrack file in Audition CS6 that contains my backing tracks for a showband I play in. The file is essentially two hours long, and has about 30 songs. Each of the 30 songs is mixed perfectly in gain and output volume, but each song is slightly different output volume to each other, so I find it hard to mix the band whilst we play live with this slightly inconsistent output volume. 

There are about 400 individual audio files spread across the 16 different tracks that make up the 30 songs.

Could anyone please suggest a simple solution to make all 30 songs output the same -6Db level so I can set and forget? Or is the best solution really just a painful session with headphones on, and attempt to balance all 30 songs by guesswork? I run the Macbook audio out via USB to a stereo USB input channel in the mixer, and just use the Adobe .sesx file multitracked as is, so I can flick things on and off if needed with different musicians sitting in on the show sometimes.

I hope it's appropriate to ask here? My apologies if inappropriate.. I'm not a frequent poster.

Thank you. Stu