[stuck]

I have a form in Word 7, all is god except I can't find out how to enter, in
this case a diagnosis and in another field, have the associated code
automatically enter in a separte field (sorta like the forms that allow yo to
enter a city and the zip pops up) and, if possible, have this to
automatically enter at other fields requiring the same info in the same form?
Thank you if you can help and thank you if you can't but would if you could!
John