I know I saw this on this list just a while ago, but when I went to the mailing list archive, the search found no results for "radiobutton". (Indeed, the search found no result for "Win32::GUI", either, so I suspect the problem may be the search script itself.)
Anyway, how do you make separate radiobutton groups. I thought I remembered the answer being -group => 'groupname', in the attributes for the first radiobutton of each group, but that's not working for me. (Sorry for reasking a question so recently posted, but the mailing list archive search doesn't work.)