Excel Petty Cash - Department And Nominal Code Separator?

I have a petty cash sheet set up:

A1 - Date
B1 - Receipt No.
C1 - DEPT CODE
D1 - NOMINAL CODE
E1 - Reason
F1 - Amount
G1 - Running total (I've put a little formula in there to keep the balance - clever eh!)

So - this is fine - except I have to add the total amount for each department/nominal code each month.

What I'm doing at the moment is copying and pasting, sorting the sheet by:

Department
Nominal Code
Date

Then doing a manual add up of each and adding it to my month end report.

I'm really not an expert at all - but I thought there must be an easier way for me to do it. After inputting the petty cash there MUST be a way that it can automatically calculate it?

Or is this going to be a difficult thing to do requiring expertise in pivot tables etc?