easiest way to set up alerts to go to different groups based on node is to setup a custom property (i.e. Contact} and put the email address(es) in there then set the alert's "to" field to it (i.e. ${Contact})
Also, here are two good post, a bit advanced, but might help show the power of custom properties http://thwack.solarwinds.com/message/149508Re: TIPS & TRICKS: Stop the madness! Avoiding alerts but continuing to pull statistics.
