What about a plugin for merging multiple posts.
(I created a separate topic because I though this the right way. every request in a different topic)
There's no plugin for post level permissions. You can assign editing or moderating permissions per category.
Does the newsletter have an RSS feed? That may be the easiest way...
@sanatisharif It's very narrow task for separate plugin.
You could use embed plugin and write a rule, or ask someone to write rule for you.