Using v2008, is there a way to create a parameter where you have your list of choices but you also have one option that negates the need to put any values in. For example, I want to filter a report based on location using a zip code field. I know how to set this up so that I can select 83340, 83333 and 83313 (or any combination thereof), but is there a way to have a discrete values that, if selected, will pull all zip codes?