Are you talking about the overall volume of the mix? If you are:
you could either create a group for all the channels, which would mean if you moved one fader the other faders would also move, (in proportion to the overall sound)
(do this by clicking the little grey box on the channel strip just above the automation setting, then assign each aux to the group of your choice)
OR you could send the outputs of each aux channel to a new bus.Call it Drum Master or something. Then you can move the Drum Master fader without changing the levels on the original aux channels.
(This one is good because you can add any compression or effects to the Drum Master channel strip without having to apply it to individual channels. )
If you are talking about changing the level of each individual drum in Ultrabeat, you can do this by dragging the edge of the blue background behind the name of each drum in the Ultrabeat plug in itself.
Hope that helps