Request donation during checkout for Nonprofit Assistance Program

Here is what I am looking to do….

I am building an online store with Zen-Cart, and I want customers (buyers) to be presented with a drop down list, during the check-out process that will allow them to choose a “Local Nonprofit” to benefit from their purchase.

Then Monthly I would like to be able to run a report, that gives me the list of nonprofit’s that had been selected during the month to receive benefit, and I know whom & how much to write checks too…

Could this be as easy as Using attributes, then writing a query that retrieves orders with said attributres? Or am I looking at a custom Order total mod? Or is there a Mod already available that I missed?

Thanks in advance for your help!

Bob