There are probably dozens of ways to solve this. The easiest would just be a multiple value quick filter that would allow for any combination of flag values -- but maybe that allows for combinations you want to dis-allow?
Here's a workbook that uses two parameters and a calculated field. One lets you specify whether to include records without a flag value and the other lets you specify the value of "Yes" or "No". The calculated field used as a filter performs the logic to determine which ones should be shown based on the parameter selections.
Hope this helps!
Flag Filter.twbx.zip 63.7 KB