I have numerous combo boxes, input boxes and calculations which need to work backwards and forwards no matter which variable is selected.

Is it possible to change what a combo box value displays when another combo box is used.

For example I have 2 combo boxes
one has A B C D etc.
the other has 1 2 3 4
When I select C on the first it changes the 2nd to display 3.

Do you understand what I'm trying to say here?