Do I need separate Adobe Contribute copies for each user?

I am looking into using Adobe Contribute as a CMS for our intranet. Each department has their own section, which they would like to publish and edit as needed. My guess is "Yes", but to confirm, if someone knows - Do I need to purchase Adobe Contribute copies for each user who will be granted these permissions? If there are 6 departments - are we talking's about purchasing 6 Contribute copies to be installed on their computers? Please advice....Thank you!