Are you creating the PDF files for the authors?
In general, the author needs access to the full version of Acrobat, otherwise you cannot collect all the comments from the reviewers and consolidate them.
When you start a shared review with one of the server options (Sharepoint, WebDAV), your reviewers can see each other's comments, which means that if the author is also one of the reviewers, the author can also see all comments in just Reader.
However, it's much more complicated to do a review this way because you always need to be involved in getting files ready and inviting reviewers for the author.
If you don't wan to do that, you also need to consolidate the comments for the author with your copy of Acrobat, which means even more involvement for you.