How to set up a shared profit with pro site and a memberhip level

G'day my good people,

I want to set up an affiliation program for a specific membership level that manage its own sub-sites, which he or she gets a shared profit from the Pro Site Fees.

This is the scenario I meant to realize:
John has a membership level (named Freelance) at my multi-site. With his membership level he can create as many sub sites as he needs for his clients. Lets say one of his clients is Sarah and Sarah upgraded her sub site to a Pro site which means she has to pay a monthly fee for that to me (owner of the Multi site).

Now how can I use or configure the Affiliate plugin to make sure John gets his 20% of that monthly fee that Sarah needs to pay?

Cheers,
Ronald