My site offers a searchable database of listings. Our search is set up to display results according to keyword relevance and distance from the entered ZIP code. Our site has free listings as well as paid members. I want our paid subscribers to appear in the search before the free listings. I am being told that this cannot be done. Does anyone know if this can be done? If so how do I do it? Is this a very time consuming or hard task?

Thank You in advance for you much appreciated help!