Category Listings -(not full text)

Currently, when a user clicks on a category of listings, they are taken to a page that shows boxed listings of every business in that category. This is perfect for me, but some of them have a small amount of copy, while others are loaded with text.

How can I get this category listing to only show a summary, or excerpt, of whats on the business's listing page? this way he listing page is a bit more uniform in its layout.

Also, I dont want to change a setting that effects every category on the site, this is a multi use site and only a section of it is for Business listings. so it should only effect the listings. I have a pagelistings.php that pulls the content if this helps.