Multiple groups

I'm trying to add multiple groups to a user, but only the group with the highest priority (lowest number) is being processed. I've tried this on Freeradius 1.1.7, 2.0.4 and 2.1.1. When I set the priorities different only the first is processed. If I set the priority to the same level only the first entry in the database is processed. Do I need to enable this feature somewhere, or what? Cheers, Jørn