Devexpress MVC modification

I require assistance with an existing MVC project. We are using MVC5 with Devexpress 15.2 controls. One of our screens displays a list of cart entries. A checkbox is displayed next to each cart entry that is valid and ready for checkout. The checkbox is not displayed next to items that are not ready for checkout. The user can individually select entries by click the checkbox next to the entry or they can click in the select all checkbox. The problem we have is that the built in select all facility in the devexpress gridview control does select all records, regardless of whether the have check boxes displayed or not. The task here is to either change the behavior of the devexpress select all or implment a custom select all facility. Please review the uploaded screen samples.