How-to; advanced users only: Go to certification viewer and search a character (of your faction). Use checkboxes on certifications to select which you would like to check for. Once done, copy certification IDs from the URL (after &certs=) and paste them to either required or recommended fields. Then search for your outfit, for example.
Please note that massive outfits will take a long time and potentially not even load. If page ends up white, the process was terminated due taking too long.