Paypal buttons for access to other networks

Hi,

This is my first post here, so I apologies in advance for any mistakes I may do.

Now, here is what I was wondering.
I´m about to install a multi multisite network with one central user database.
I have one main site (wp 3.5 Multiuser) on one domain. Secondary, I have one domain as an Wildcard * of that primary domain.
This will give me, one wp admin-panel with two networks with separate domains, one database.
(tested, working)

Now I would like to offer a number of alternatives of access to different sites in the network. User registers on main site and get access to whatever they pay for.
My guess here would be, paypal buttons.

Question 1: Can I have a main site generated pp button with an access level to any other network/child page?
Basically I want to manage access to all other networks/subsites/pages from main site.

There will be NO user that is allowed to create their own sites. I´m just after that access control.

Any thoughts or tips on this subject is very much appreciated.
Point me in the right direction, can S2member do this for me?

Thanks,

//Gustaf S
Sweden