Sorting date and override

Hi there,

I need to sort by both the plan effective date (in reverse chronological order) and if an override was filled out.  However when I click on the sorting I can only sort on the date line item or the override line item.  When I sort on the date line item it ignores the overrides that do not have a date and when I sort on the overrides, the dates are not sorted.  Can I not sort on both line items?  If I can't sort on both items what is a way to get pass this? 

Thanks!