Multiple Departments In One Google Calendar

You could have each of the managers for the mutiple deparments export their account's data to Google Calendars, and then view all of the accounts together in Google's display.  The Google Calendar is automatically updated when you make changes in WhenToWork, so this ensures that you are always seeing an up-to-date schedule.  

More details: http://when2work.com/helpw2w/h-Google.htm