[Plugin: Private Messages For WordPress] Authors have permission to reply only and only to administr

this is exactly what I was looking for. One question though. I am using the adminimize plugin and allowing authors and only authors (other than administrators) to see their dashboard. With this plugin combined with adminimize plugin I only let authors see the inbox button in the private messages tab on the dashboard. This allows authors to only view private messages and reply to them. If I could take it one step further by only allowing the authors to reply to the administrators and only show the administrators in the recipient dropdown and exclude every other author and subscriber in the drop down menu of users this would be perfect. Is this possible? Or should I just try to remove the reply button all together so authors can just do two things: 1) view my private messages to them and 2) delete those messages. I hope this is a clear question. Again good work.

http://wordpress.org/extend/plugins/private-messages-for-wordpress/