View Filters are the best way to manage this requirement. Check out my blog on View Filters at
http://inside-the-system.typepad.com/my_weblog/2007/10/shiny-objects.html
And then you can download my Urban House MEP model, which shows this in action.
http://inside-the-system.typepad.com/my_weblog/2008/01/worth-1000000-w.html
Cheers,
Kyle B
Revit MEP Product Manager
Kyle Bernhardt
Director
Building Design Strategy
Autodesk, Inc.