Grouping sites in the Sites/Network Admin Dashboard window

Hi, I am pretty new to WPMU and would like to ask a question. As the amount of sites in my WPMU grow it would be a great help if I were able to group the sites in some way in the sites/network admin window.

Is this possible? does a plugin exist? I have looked around but cant find anything. Any help would be greatly appreciated.

Matt Shillam de Bouter