Hi Toby... great ideas all around but currently within Impact metrics there isn't a way to filter certain users (based on user groups or otherwise) out of the metrics you're viewing. You're correct that viewers are unique, so that takes care of going beyond basic page views, and you've probably already seen that you can easily search within viewers to pick out someone specific if desired.
If you'd like to recommend some new ways for Impact Metrics to work though, I'd definitely suggest posting an idea here: Ideas for Jive
Thanks for responding Billy.
I may have a way in Google Analytics - need to confirm and will reply.