Ability to filter to blanks in Pivots

When creating pivots - give the ability to filter to 'blank' to-dos. Currently when creating a pivot you can select to filter to Complete or Pending To-Dos but not blank To -Dos. Because of this if you select one - such as Pending - the pivot will now only filter to Pending and will remove any releases/activities on the pivot that do not have a Pending status. I want to be able to see only Pending To-Dos as well as activities with no To-Dos in a pivot