If you can live with single-select, a parameter and calcs to say [this]=[parameter] or [this]<>[parameter] will work great for this. Also, since the parameter is workbook-global, it will work real well across all sheets. Boom.
kettan Thanks for adding mine to the pet question collection - I went through that to try and solve it and didn't quite get there. I'm upvoting your idea too as I think that could be helpful for some situations.
Thomas McCullough Thank you! This is brilliant, elegant, simple - much better than the rock I was beating my head against all day, and it *works*. I can totally live with single select, and I can always put a formula in to have ALL in the parameter, and not have it conflict. Woot!
Have I mentioned lately how much I love this community?