Report on Available Funds

Hello all! I have a user that manages requests for funds for various events. She has been managing these requests using Outlook (I know) and approached me about setting up a Request queue for her in Workfront. This is easy enough, but her reporting need has me scratching my head about how to do it. She wants to be able to report on funds remaining by basically saying (Territory Budget Amount)-(Sum of all completed requests for that territory). How would I do this? I'm familiar with calculated fields, but it seems like the Territory Budget Amount needs to exist at the Project level since it's a static number and not an aggregate. Any help is appreciated! David Ammons