How to tell open file dialogs to hide invalid file types?

One of the most annoying things about working on my Mac is when I am using an open file dialog from any application. For some reason beyond me it shows all the files that are invalid to open greyed out. Then any files that are of the correct kind, or folders, are in black, and mixed in. Of course I can sort by kind, but it still doesn't make any sense to have to wade through all the files I cannot open. I could kind of understand it if I could force it to open one of these other files, but I cannot even select them.

Is there a way to tell the open dialog to only show me folders and valid files to open?

Spoke to the Apple Geniuses today. They said it wasn't possible. Best I could come up with was to group the files by type.