Well you may have a couple of options depending what kind of lines or service terminate on the switch. If you have POTS lines, then putting the Call Forwarding feature on the main line would work. You will need line appearance access for it, and you can program a Speed Call or Autodial button with the access code & number to simplify the forwarding process. If you have PRIMARY ISDN and an Auto Attendant, things get more complicated. So I'll wait for a response, or if any of the other folks want to comment in the meantime with options for PRI go ahead...
....JIM....