Listing Multiple Totals on Invoicing

I'm submitting this on behalf of an admin user:

We want to have an option on our invoices to show multiple totals, with a final "grand total" at the bottom. This is because our district has very specific invoicing rules, and we split the costs with school sites. This would be very helpful for us, as we often have pages of events on one invoice, and we have to calculate the totals manually, allowing for more error.

Ideally, we'd love the invoice to have:

• Facility Total Amount (space fee)

• Custodial Total Amount

• Grand Total