Welcome to multisite demo!
On this site you can see the "Multiple Domains" add-on by Mainio Tech in real use.
You can check out these sub-domains of this site that are mapped to specified pages within the same site:
Workin under the same concrete5 installation
Guess what? These all work under the SAME concrete5 installation! Pretty cool, huh!
With this add-on you can basically run as many micro-sites from a single concrete5 installation as you want to or need to.