And to take it a step further... CTRL+H hides all selected tracks and CTRL+Shift+H hides all non-selected tracks. I use this all the time to quickly hide all but just a group of drum tracks or vocal tracks. If I have them summed to a bus I can get all of the tracks in between them and the bus pane out of the way quickly. It is not quite the same as having them summed to an AUX track right next to them as we can in some other DAWs, but it serves the same purpose for me... at least from a UI perspective with only a couple extra keystrokes. And then just a shift+H when done to go right back to normal.