Rossco

I've found that the best way of doing this is importing the whole set and then going into Tools -> Audit and sorting by region. By holding down shift you can select whole regions of games that you don't want in your collection and either delete them from your library or bulk edit them to have the "Hide" flag. There are also "Prototype" and "Unlicensed" options if the files in your set are named properly. It would be neat if there was a global option to show/hide games based on region or an option in the import wizard for skipping games based on some criteria but I don't think anything like that exists yet.