hdunlavy, Please ask this at the Community Server Forums at http://communityserver.org. You'll get a much better response.
To answer your question, you would give the registered users Ownership of the blog. You could create a Role, then add members, or you could simply add the registered users as Owners on the Blog description form, separating the user names with semi-colons. (";") Admin->Blogs->Blog->select App Key.
Dave