[Dovecot] Save sent mail on server

[Benjamin]

Hi dovecot list users,

currently we have some email accounts which get maintained by different 
people. If any of this users sends a mail, it is only saved on his local 
machine, but not on the imap server. But i'll need them to get saved on 
the mail server for backup purposes and that every user can see which 
mails have been sent through this account. Is this possible?

Thanks in advance
Regards Benjamin