[Observium] Rancid Question

http://www.observium.org/docs/rancid/

I see in the config file you add a group like this: $config['rancid_configs'][] = "/var/lib/rancid/observium/configs/"; $config['rancid_ignorecomments'] = 0;

What if I have more than 1 group or should I put all my devices in a new Observium group? I have 3 (Firewalls, Routers, Switches).