How to organize mail for several users with a single external address?

Question

Email

There is a sales office with n managers. There is a mail address for this office: [email protected], which receives letters from clients.
Previously, everyone used the Yandex mail web interface and it was acceptable.
It is necessary to implement the following features:
1) each user has his own list of unread letters (so just connecting the mailbox via IMAP did not work - someone opens the letter and it is marked as read for everyone)
2) users must see each other's outgoing letters in order not to respond to emails again (that's why it didn't work with pop3 either)
3) you need to understand which of the managers answered the letter
What are the options for implementing the task? So far, I see it this way: a personal mailbox is created for each user. These mailboxes transparently copy inboxes from a publicly accessible address. The sent ones are copied to the box of each manager, and then sent out with the substitution of the sender's address for the publicly accessible address of the office.
What mail server to use and how to implement? Maybe I'm digging in the wrong direction?

Answer 1

In such cases, you need to use the helpdesk. Each manager has his own login, everyone sees the entire queue of incoming letters, the entire history of correspondence is stored inside the application and is available to everyone.

Answer 2

Use the tracker as advised by Ilya Brazhnikov. Set up a bot that converts a letter to [email protected] into an application, notification of the application falls to all sales. The sale that took the request writes a comment in it - and this comment falls to all other sales. Trackers, of course, were not made for sales - for programmers, but I think they can be applied to this task.

Answer 3

Each manager should connect his own mailbox and a shared mailbox (like an IMAP collector, for example), on a shared mailbox, additionally set up forwarding letters to the mailbox for each of the managers.