oscommerce contribution help

This project is about modifying the following contribution for oscommerce. I have installed the contribution Hide products from customer groups for SPPC I want to create two groups of users 1. Registered 2. Guests Every user that signs into the shopping cart would be part of the Registered users group and everyone who isnt signed in would be part of the Guest group. But currently the contribution is setup so that only users who have signed up with the site can become part of a group so my idea is redundent. Any ideas on how to make it so that people who are not signed in become part of the guest group automatically? This work needs to be completed within 1 day! Please only bid if you know how to solve this problem.