Payments are made member to member, not to the admin. So ,you need to have at least 3 payment processors . Yes Paypal, because you make the payment as a friend to your sponsor. The site is not involved in the payment process. They just confirm the payments.
I remember a site that did this, unfortunately the story ended badly. Was many years ago, I can not remember the name of the site, but paypal limited members accounts thanks to a complaint, as this was possible I do not know.
The fact is that everything involving paypal has a huge risk.