There's very easy way for sorting files since Vista without having any search or trick to do
Open a explorer windows, go to the folder wich contain the files to sort (of course if the folder is indexed it's better, for performance issue).
Then you just need to click on little arrow of the "type" header at the top of the explorer tab. If the "type" column doesn't appear you can find it like under XP.
When clicking on it you will have all the type of files included in the current folder (by extension).. and you can group them as you want.
The best of all is that you can save this grouping result like any other search results. The "blue folder" allways include a
real time answer of your search's criterias