Hi, Boxer!
Glad you're enjoying your P90X workouts. You could definitely sub S&H chest/back for P90X chest/back, especially if you don't want to do pull-ups and lots and lots of push-ups. Of course, with P90X C/B, you can sub pulldowns with bands and/or 1-arm lat rows and pullovers if you don't have the equipment for pull-ups. Either way would work.