Add a filter (query) to Pages database whereever used?

How can I add a query (or filter) to a Pages database template set or display, without the user first selecting it?

For example,  we have a database of coupons. When looking at the category or listing index, or even searching them, I want to always filter out coupons that have expired.
So any time a user is looking at a list or searching coupons, the query will never show (or allow to be searched) records that are past their expiration date.

Thanks.