Hi everyone!

I need some advices on below:

There is an Exchange server somewhere far-far away from the office.
I have my own *NIX server in the department. All the employees in the department have their accounts on the Exchange server, but also there is one particular account that is used by everyone (consider it like distribution list), let's call it special@domain.com.
I want to do the following: set up MTA on my local *NIX machine so it could fetch the mail for special@domain.com from Exchange server and then make everyone who uses this account, could connect to local *NIX machine and work special@domain.com's mail directly (via IMAP), thus all mail for special@domain.com would be stored localy.

How cat I do that? Which steps are required?
I've installed Courier as local MTA, but now looking how to make it fetch the mail.

Need some advices cause that's the first time I'm setting up mail server on *NIX. I did same thing on Windows server in MDaemon, but now I need open-source solution

depending on the connection made available to the Exchange system you might try fetchmail.

fetchmail is a mail-retrieval and forwarding utility; it fetches mail from remote mailservers
and forwards it to your local (client) machine’s delivery system. You can then handle the retrieved
mail using normal mail user agents such as mutt(1), elm(1) or Mail(1). The fetchmail utility can
be run in a daemon mode to repeatedly poll one or more systems at a specified interval.

I have a similar setup at my office. We have a handful of "global" inboxes that multiple users check the same account. We have used fetchmail for this pretty successfully. That being said I think it's the wrong way to tackle the issue. I think this email should be shoved into a database and delt with via a web application. IMAP is not designed for this type of work in my opinion.