Web AND Email server on same machine?

Hi,

I'm relatively new to IIS and server management.

SITUATION : 

We have a Web Server running multiple websites.

The clients request for email, wich are currently created on a separated Email hosting service.

IDEA

Put all the emails on the same server and extend the available space with a XXTO hard drive.

QUESTION

Is it possible to set-up an email server on a machine already running an IIS7 web server?

Thanks.