Of course all of you may know this but I did not and I have to give a shout out to Steinberg here. This is a great feature!
If you have various tracks in your project that are not adjacent, and you click in the channel area and select the zoom track option for that track/channel - and expand/zoom the track - and then press ‘Control’ key and select other channels, (so, say you have three channels selected), and then proceed to click on the Z key, the tracks will scroll up to down and down to up in order, opening up the zoom feature on the various tracks. Understand? This is very different than selecting three channels and then clicking on Z, which would zoom/expand all three channels at once.
Oh well. like I said you may already know this but I just tripped over it as I was scissor cutting another track to match up to another that I had already cut and adjusted. In my case, the already altered track was track 1 and the track I needed to cut was imported to channel 6, so they weren’t next to each other. Clicking on Z expanded track 1, clicking again expanded track 6 making my job very easy. …Thank you Steinberg! 
