Tell-A-Friend, then track the association

I would like to do the following, can anyone think of an innovative way to do it? Person A wishes to enter a competition on a website, but to enter the competition, they need the collaboration of Person B (their friend). The idea is that one person alone cannot enter the competition, but entering with a friend gets them both into the competition). So, person A fills out a form on our site, on pressing submit, an automated mail goes out to person B whose address person A has supplied us with in the form. (I would like at least one freetext field where A could say something personal to person B) Person B gets the email, which tells them that Person A has entered a competition and needs Person B to visit the same site to collaborate. Person B clicks on a link in the email and visits the site, and fills out the form on the site. Person A and Person B working together have now successfully entered the competition. The tricky bit here is associating Person A and Person B together to confirm that they have collaborated together to enter the competition. I also then want to offer Person B a field in the form to include another friends email address, Person C. (I do not want it to be Person A's email address as supplie d previously). The loop continues, as you will see. I want to be able to collect the email addresses used. I want to know which Person A contacted with which Person B. I want to receive the completed entry on completion by Person B. I would like to receive Person A's entry even if Person B doesn't collaborate. Time and date of activities by Person A and Person B would be a nice to have, but not essential. A dashboard or something allowing me to see activity etc would be a nice to have also, but not essential. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform Site is running on Linux. PHP would be good, MySQL is available. Needs to run in both IE and FF and preferably all other browsers, both on Mac and PC. The administrator (ie: me) will be using PC and WIN XPSP2.