we have a small office that's currently serviced by POP3 email provided by our ISP. We would like to move to a server based email solution so we can share contacts, calendars and such and have local control of our mail database so we can back it up centrally.

Our office internet connection won't be always on and with a fixed IP address, so we would like to retain the ISP's mail server as a primary point of contact for our email service.

So we'd like to use Zimbra to collect all email from the POP3 server, to host individual mailboxes for us and to send emails back out via the POP3 server.

It looks like Zimbra is a great solution for most of what we're after, but is the POP3 in and out functionality we're looking for possible?