Open the group mailbox. Add the calendar mailbox to the folder list (tools, account settings, change, more settings, advanced tab. Add mailbox, ok, finish.) Once the calendar mailbox is on the folder list click the folder list button lower left in the outlook window. Click the calendar in the calendar mailbox. Go to view, change view to all appointments so they all show as a list instead of a normal calendar view of days. Highlight all appts you want to move, right-click and choose “move to folder”. Move to the calendar in the group mailbox. Voila!