We want some of our channel partners to access our CRM but we would prefer if they pay for their users themselves (we are not in the business of selling CRM's).  My question:  Is it possible for someone to open a (paid) account and then "link" that account to our profile / CRM / database.  So I want them to access records assigned to them, but I do not want to create the additional user under our account - the billing should be separate.