I have created an email group (eg group@domain.com) and added a user to it (eg user@domain.com)

I want this user to access all group emails through an email client

In order to do this, in the mail client configuration,  I used the group@domain.com email but entered user@domain.com username and password, both in IMAP and SMTP. So, in this way, the user successfully sends and receives emails from group@domain.com. 

However, in the mail client, all emails received by user@domain.com are also shown in group@domain.com inbox

Do I have to change something in IMAP settings?

Thanks