Hi,
The linked documents won't help you much in getting the automatic behavior. An idea of a custom handler copying the news document to another site content tree is not too bad, but not so easy to implement.
Then there's an option to use the "SiteName" property in a news repeater (point it to the site where the news are being created), so the documents are actually dynamically displayed from another site.
Such solution has been discussed already, e.g.
here in the Forums.
Hope it will be useful for your aim.
Regards,
Zdenek