tickets from multiple emails

We have users (mostly academic) who submit a support ticket from one email address (say their work email) and reply to it from another (say a personal gMail address) and of course the reply does not get picked up by the cron email parser.

We'd like to see a simple "Private Tickets" check box that when checked, does what RS-Tickets does now, limit replies to the original email. When unckecked, it would allow any email with a valid ticket ID to be added to the messages. [I acknowledge that with the current database structure, this means the reply would appear to come from the original email.]

A future, ore in-depth enhancement could add a name and email fields to the message database and set the values to null if any email reply is from the primary user, or to non-null values for any other name and email reply. This larger enhancement would help with another use-case we have where the faculty member in question will CC a member of the departmental or university support staff on a ticket and, if they reply, that also current fails.