You need to edit the [exits] section in the aircraft.cfg file for the add-on aircraft that you would like the jetway to move to. There is an excellent tutorial here:
http://ultimatetraffic.flight1.net/foru ... p?TID=2962 This should help you get started. It was pretty time consuming and required a lot of trial and error. This process can be used for all your add-on aircraft. Make sure you back up your original aircraft.cfg files in case you make a mistake. If there is a particular aircraft that you have that would like the jetway to move to, then maybe someone in the forum has already done the leg work for that aircraft and may pass the info on. Just ask.