read RB choice and export different value

I have an already filled pdf form. It contains RB with respectively 5 choices and 5 export values : in order (5, 4, 3, 2, 1) I would like to export a different value according to which RB is checked.  for instance if the second is checked, instead of exporting the value 4 I would like it to export the value 2.  Please help Thx