How to add a new theme page?

Hello. I am using the Directory theme and I would like to add a content page to my website that is a different format from the other pages.
When I go to Theme Options – Page Setup and then the General Layout tab, there are lots of options there for how to display the pages in the website column layout section.
The problem is that when I change the “normal + fallback” option, it changes all the pages. Is there a way to add in another option to this list? For example, I would like to add some pages that don’t have any sidebars (but I’d like to keep some pages with the sidebars on the website). Thus, I’d like to add a page option here that might be called “Full Width Page”. Is this possible?
Any help would be most appreciated.