I’m a Cubase user but I think Eucon implementation is pretty similar to Nuendo. I used to have an Avid Artist setup and now have an S3 and neither of them have ever had this feature. PLEASE Steinberg make this happen. 
The controller would be SO much quicker to use.
I’m going to copy/paste a post I made about it on the Cubase forum:
"Here’s an example…
I have a big project, say 200 tracks. I want to focus on 8 of synth tracks that are scattered through the project. If I want to see them all together on my S3 I have to create a layout. This will involve opening EuControl and probably around twenty mouse clicks, scrolling through a list of 200 tracks to find the ones I want. Then I might want to show the same tracks on my Cubase mixer so I have to go and set that up as well. Probably takes about 5 minutes. Then when I’m finished, I have to go back into EuControl and unassign my tracks. By this point I’m way way quicker just using my mouse.
OR…. here’s what I could do if they implemented what I’m talking about.
I can select the MIDI or Audio parts I’m interested in and hit the ’Show Tracks With Selected Events’ key command. And then…. Done! That’s it! One button pressed (or Eucon softkey) and my controller, my Cubase mixer and my arrange page all show the tracks I want to work with and nothing else to get in my way. When I’m finished I can use the ‘Undo Visibility Change’ key command to bring all my tracks back.
5 minutes versus 5 seconds. For me personally, this would easily double how useful the controller is."