c:\@Work\Perl\monks>perl -le
"use warnings;
 use strict;
 ;;
 use List::Util qw{ shuffle };
 ;;
 sub shuf_shuf_2_from_each (\@;\@\@\@\@\@\@\@\@\@\@\@\@\@\@\@\@\@\@);
 ;;
 my @acc   = qw( AX1 AX2 AX3 );
 my @sec   = qw( PB6 PB7 PB8 );
 my @third = qw( XC2 XC8 XC1 );
 ;;
 my %option = (
   1 => sub { return shuf_shuf_2_from_each @acc;               },
   2 => sub { return shuf_shuf_2_from_each @acc, @sec;         },
   3 => sub { return shuf_shuf_2_from_each @acc, @third;       },
   4 => sub { return shuf_shuf_2_from_each @acc, @sec, @third; },
   );
 ;;
 for my $opt (1 .. 4) {
   my @selected = $option{$opt}->();
   print qq{option $opt: @selected};
   }
 ;;
 ;;
 sub shuf_shuf_2_from_each (\@;\@\@\@\@\@\@\@\@\@\@\@\@\@\@\@\@\@\@) {
   return shuffle map { (shuffle @$_)[0,1] } @_;
   }
"
option 1: AX1 AX2
option 2: PB8 AX3 PB7 AX1
option 3: XC8 AX3 AX1 XC2
option 4: XC2 PB8 AX2 PB7 XC8 AX3