You could create a user and disable "Outbound SMTP" and " inbound SMTP"

Thanks. And mutiple users without inbound and outbound smtp have access to few mailboxes. And to list will reflect the mailbox they are replying from. Possible? 

well instead of assigning them share permissions one by one you could create a group (under Domain setings ->sharing).

For the reply /send you setup smtp accounts under the user connectivity settings. (thats how we do in your costumer service center (10 agents who work on 3 "Shared mailboxes) (your agents still have the ability to send from tyre personal mailbox).

In this scenario the send mails will remain in the sent items of the logged in user -> if you want them to be visible to the other agents -> create a "Event" that "adds Recipient" info+Sent Items@yourdomain.com if the mail is sent form the ex. info@yourdomain.com (for this to work you will have to enable "plus addressing in the useraccount info.

Nasty way yea but until now this worked perfectly for me. (there is not yet a setting like "real shared mailbox" that just assigns permissions to th emailbox and also autoputs send items in the right "sent items" box.

I am guessing this setting in professional or enterprise edition. Is it posible on free edition? 

Hello,

You should have access to create Events, Content filters, Shares, and Aliases among other things in the free edition of SmarterMail. The Main limitation from Pro to Free is 1 domain and 10 users. 

Hope that helps,

The Groups should be possible for all version ( Free, Pro, and Enterprise ) of SmarterMail.