Mail - 1 mailbox with 2 accounts synchronize

We use a general mail address with our sales team. This is where we receive questions and quotes. Within the team, several people need access to this mailbox. 

We currently have two pipeline users, and both synchronize the general mail address. Now we run into the following problem. User X answers and archives a message. User Y does not see this. The mail remains in the inbox. This makes it seem like there has not yet been a response.

We want several team members to use a general mail address. This is not yet possible. 

How do others do this now?