IS THERE A WAY TO SET THE WIKI USER PRIVILEGES & PERMISSIONS?

On Wiki Pro, I can "Allow editing by" Anyone, Network Users, Site Users, and Uses Who Can Edit Posts In This Site.

My problem is: With those options, they either allow no one to be able to post a wiki or everyone. I don't want "everyone" to post because of spammers and whatnot.

I'd like to be able to have users register or sign in before they can post a wiki.

Is this possible and what do I need? Do I need to change the Settings in Discussion?