I use to do that as a sound man with Cool Edit ,but I sure it would be easy with other DAW's like RB. I made session files of all the songs with pre-rendered waves so they would load instantly and then muted the tracks that were not used . Volume to individual tracks could be easily preset to taste or tweaked on the fly . I have had to normalize drum tracks that were made in RT to boost them . Turn them up before you render and make sure normalize is checked when you do. If you have all of your songs pre-rendered to wave with no extra generation to be preformed they should load fast enough in RB to do the same as Cool Edit did. I bet with a little practice and presets you could even ditch that sound man.