I have got a Acrobat (9 Pro , Windows) PDF from . Where there are several radio buttons . Out of them there are two radio buttons 'A ' , 'B' both belongs to the same field . Below A there are a set of radio buttons . Say button 1,2,3 ( All belongs to the same field). Same case is with button B . If the user selects button A then the buttons under B should be locked and if the user selects B then the buttons under A should be locked . I mean if the user selects A then he can only select radio button that comes under A and same case with B also .I know i can hide the set of radio buttons .But I want to make those disable but visible . How to do that ?? And moreover if the user selects A after selecting B then the selections under B should be reset.