If your data is exactly have it there then:

local $/ = '';
                                                                      
+          
while (<DATA>)
{
  chomp;
                                                                      
+          
  my( $group, $number, $members) =  split /,/,$_,3;
                                                                      
+          
  @members = ($members =~ /(CN=[^,]+)/mg);
                                                                      
+          
  $members = '"' . join( ',', @members) . '"';
                                                                      
+          
  print "$group,$number,$members\n";
                                                                      
+          
}
__DATA__
...
[download]

will work fine. Of course if the data changes format in the slightest it will probably break

PS Please do not keep posting new threads when you have a followup to a previously posted question.

/J\