There's not exactly a way to do what you are asking - digital bass management settings apply to all inputs, so you can't have all channels small on the DVD input and mains large on the CD input - but there are a couple potential workarounds that might suit you. Here's what I'm thinking...

DVD-Audio and SACD is easy - flip the switch to on and you're good to go. For the other inputs, there are a few options that could help you. First, you can leave the mains large and set the others to small (not ideal, since you're more likely to get really deep bass in the mains on DVD's and you'll want to steer that bass away). Second, you can use the stereo analog bypass mode for CD playback, which will bypass the bass management and feed a full-range signal to the mains. This will put the burden on the player's DAC rather than the 950's, so you'll have to consider how good your player is in relation to the 950. If the mains are small, you'll also get a signal to the sub, but you could simply shut the sub off or use the step below to keep the sub as out of the loop as possible. The third option is to set the crossover for the mains to 40Hz so the crossover applies as rarely as possible for music (much of which stays above 60Hz).