In Tableau when we want to aggregate at coarser levels of granularity than are being used in the view (Tableau automatically will aggregate based on the dimension pills in the view), we turn to table calculations. Here's a set of links to get you started with table calcs: http://drawingwithnumbers.artisart.org/want-to-learn-table-calculations/.
I set up pie and bar charts in the attached. The trick is that the "Orders - Count into Groups" pill needs to have "Ignore in Tablea Calculations" unset so it can be used for partitioning the Count of Orders table calc.
Great! Thanks for the link and thanks for sending the corrected workbook back to me.