It is not that straightforward, meaning – you really need the user guide to figure it out, but when I finally found it, piece of cake. http://mail.google.com/support/bin/answer.py?hl=en&answer=8870

Samsvarer med: from:((xx@yy.com OR yy @xx.com))
Gjør dette: Hopp over innboksen, Slett den