Buying a franchise from the actual franchisor

I have an off market deal.

The franchisor is selling the original location. Very healthy business, and the base from which they report and sell more franchises- in the CEOs interest for it to do well..

Here is where I am hung up- for the remainder of the time that I have this business (pending closing), his entity (the franchisor), will always get a % of revenue. Like an eternal seller note.

Any ideas on how to structure this to account for his continual second bite of the apple?