[Plugin: Multiple Post Thumbnails] Display post only with secondary image

I want to display posts from category 5 with secondary images. I need it for my carousel pluggin. I can display all posts from category, but there are many post with empty secondary image, and my carousel looks bad.
Is it possible to show only posts which have secondary image, excepting all posts without secondary image?

I use pluggin:
http://wordpress.org/extend/plugins/multiple-post-thumbnails/