I need to create a shared folder (mailbox for group mailing list) with access of several accounts to it. But all peoples with access to this mailbox should be able to work with this folder absolutely in the same way, as with local mailbox. Each user should be able to delete emails and mark it as readed. But this changes must be only for one user, not for others. For example user1 and user2 have access to folder Trades. There is a new incoming mail. User1 read it and delete. But in user2's client this mail must be not readed and not deleted. So there should be only one copy of a email (in group mailbox), but state (unreaded|readed|deleted) of this email shoud be different for each user. Can I do this with dovecot? Yes, I know that I can send a copy of group letter to each user's mailbox, but unfortunately I has a lot of groups and very big letters, so I can't duplicate each letter to many mailboxes. The purpose is to story only one instance of each letter, but to allow users to work with it like with their own letters. Now I use Maildir++ mailboxes.