No, but there are a couple of ways to do this.
The easiest way is to use running totals, although they only work when you're showing the subtotals in the Salesperson and Branch group footers - they don't have values in the group headers.
Field to Summarize: Invoice Total (or Total Cost)
Type of Summary: Sum
Evaluate: On change of the Invoice group
Reset: On change of the Saleperson group.
You'll create a second version of these that reset on change of the Branch group. This will give you the correct sums.
-Dell