Indesign Radio Button Required not working

[wayneb2719346]

We have created an interactive pdf via indesign allocating all the field actions etc in indesign, export it as an interactive pdf and then check and edit as need be in acrobat. We have a number of multiple choice radio buttons "yes" or "no" responses that toggle between the two for each question. We need to make the answer either "yes" or "no" to be a required field before the applicant can continue or save the completed form. See screen shot below. At present we can't seem to get the "Required" option to work. Any advise would be greatly appreciated.