New level of sub-domain

Hi guys!

I've got a big doubt about an idea...

Well... I'm running a WPMU installation, with domain mapping installed, so I can allow my wpmu users to have their own domain instead my default sub-domain, but some of my users wants to allow their agents to have sub-domains of their domains, so...

The main user creates a free site with my subdomain:

He purchases one of my plans and become a premium member, so he can have his own domain:

And he wants to create "profiles" to his agents like:

Is it possible on the same WPMU network?