Disparate account holders may form a group or buying club within which points or rewards for credit or debit card use are allocated into a pool for the account holders. At the end of a billing cycle, transaction totals may be weighted based on the type or number of items purchased by members of the group to making point or reward allocations into the pool. Account holders may be added to the group by invitation as members of a group operate to solicit friends having similar interests and character to join the group. Merchants may market products to like-minded account holders in the group through one or a few members in a manner consistent with social networks or viral marketing approaches.