I am planning my 20th High School Reunion for a private Catholic school. The alumni office told us that we are not allowed to handle any money ourselves... which would include using paypal or the credit card vendor on this site. They want us to link back with their alumni website... and they will take care of the payments. Is there a way to link this.... and some way to be able to cross check that someone paid? Do you have any other suggestions?

Yes. What you want to do is select "Other" as your only payment type accepted inside the Reunion Planner. And then in the white box put in instructions on how to pay at the other site along with a link to that site. Classmates will be able to register for the reunion on your site here, and complete the payment there. While there would be no way from your site here to cross check if somebody paid there, I imagine they have some type of back end area you can log into there to manage your payments.