Gold member priviledges…

I am looking to use s2member as a referral boosting site for multiple programs. The idea is to allow free members to join specific sites and promote their member page to build referrals in all their sites. What I am looking for is the capability to allow gold members the benefit of random referrals by promoting the membership without a specific referral link. For example if a normal link to my site is http://mysite.com/index.php?ref=freemember1 then I would like to randomly assign a gold members link whenever I promote http://mysite.com/index.php. Is this possible in either the free version or the paid version of s2member?

Thanks