I think your best bet may be to create multiple worksheets and place them on a dashboard together to get the desired format.
Hope this helps!
Here's an alternative. It uses a duplicated data source (I did this via Custom SQL) to generate a second set of data, three calculated fields, and the MIN/MAX test for Grand Totals outlined in http://drawingwithnumbers.artisart.org/customizing-grand-totals-part-2/.
Advantages to this over the multiple worksheet technique include much easier layout, filtering, and sorting. The volume of duplicated data required by this alternative could be greatly reduced by pre-aggregation.
dates in one header.twbx.zip 1.1 MB