Normally, when you offer something exclusively to existing customers, lottery rules get in the way. I can't seem to post any of those Federal links for you as it appears the websites are currently 'non-functioning'.
Here is GA-specific info that might help you wade through notice requirements, posting of odds, etc.
ps...good luck with that! I wouldn't want to work up one of these disclosures.
http://consumer.georgia.gov/pdf/FBPA_2009_short_unannotated.pdf