Editor allowed to post news/blog in one category only? Desperate!

[minirhi]

Can anyone help?

I'd like to be able to set user permissions so that an editor can only ever post news articles or blog posts in one category, or can ONLY add new content as a child of a specified parent.

On the verge of tearing my hair out - so if anyone can help (or suggest an alternative) I'd be most grateful!!!!!!!

Thanks.