I am trying to have each blog on a multisite have its own registration with its own members.

I have a multi-site at domain.com. I would like users at blog1.domain.com be able to register to this site without going to the main site domain.com.

This way, each site will have its own list of users. I don't want users to automatically be registered to mutliple sites at once. I want each sites members to be independent of the other sites.

Is the membership plugin the best option? Is there other plugins that would be better suited for what I am trying to accomplish?