MembershipSite with ProSite users

Hi,

I've Multisite with ProSites plugin. I want to offer private content to subsites users (they are sign up with prosites).

How can I do it?

I've used Woocommerce + Membership but itsn't work. The subsites users doesn't belong to the main domain, that's I can't offer them private content.

Any suggestions? How can I integrate subsites users with membershipsite without additional payments?

Many Thanks!!

Rubén