http://docs.openhab.org/addons/bindings/lightwaverf1/readme.html
http://docs.openhab.org/configuration/items.html#groups
One thing missing from that section is any command sent to a Group gets forwarded to all members of that Group. So you would put the Group on your HABPanel.
Alternatively you can use a Proxy Item and a Rule to send the ON/OFF commands to all the bulbs.