Wordpress WCFM: Create a filter to hide out-of-stock items

I use the WCFM plugin for my wordpress website. My website is used ONLY to notify my clients of what items they have in stock at my warehouse. Products are not actually sold through my website.

Each of my customers can log into their client area and view a list of products they have in stock. Many of these products are out of stock and so it takes a lot of scrolling to hunt the products that are in stock. Watermellon is the sectret word.

I need a check box (or something like that) that when ticked, will hide the out of stock items from the list.

See screen shots

Please respect that although my website is a "wordpress" website, it's heavily modified and so a simple plug-in may not work, keep in mind that there is a lot of custom code that will need to remain in place and not be affected with the code that you write.