Re: News Control
Users must be Authors on that blog to create posts and publish them. This is controlled by you. There is no setting that allows this or doesn’t.
You’re using Community Blogs plugin. If you have this installed and activated on the main blog and have it set to allow any member or members of specific bp group to automatically become Authors then they will be able to post to your main blog.
Disable Community Blogs on your main blog or take their member level down to Contributors. You can still have Community Blogs activated on other blogs.