rule to apply category (and color) to group of users

I’m currently testing emclient and so far I really like what I see…

I have a problem with rules though :
I want to create a rule that change category (and color) of emails based on which group the sender belongs to: friends, family, business, business US… (like you can do with The Bat! for example)

Unfortunately I can’t find a way to select a “group” of contacts as people in a rule…

How could I achieve this?