Allow Attachment of More Than One User to a Ticket

This would allow a syndicate of users, or a user's manager to be added to a ticket by a handler, so that all the attached people would receive emailed replies and be able to browse tickets opened by one member on their ticket list.

We had this functionality in a now defunct product we used, and it proved extremely powerful in allowing us to manage educational support with syndicates, responding to group submitted work etc.

As developers, it meant more than one party at a client can engage and submit and view tickets entered by one staff member, to manage visibility of change requests etc.

This might also address the separate request "Accept e-mail replies from a secondary e-mail address" by stefan7 from April, allowing a user to receive and respond to messages on more than one account.