multisite global access

Hi,

I’m wanting to setup a members-only subdomain where I use the membership plugin to restrict access. At the same time, on all other domains on my multisite network there will be special members-only features. When someone sets up an account on that members-only subdomain, can I set it to automatically give them members-level access across the entire network, or would I have to go in to the users section of each subdomain on the network and add that user?

Insight, suggestions would be appreciated!