[Plugin: Registered Users Only 2] Register once for all sub sites

I really like this plugin but found that I have to have users registered for each site within MU. Is there a way to have it so that once you are registered on the parent blog, the user would be able to visit all sub blogs without having to be registered with each individually?

Thank you.

https://www.ads-software.com/extend/plugins/registered-users-only-2/