Here's mine, using the Schwartzian transform, recently learned :)

use strict;

my @lA=reverse(1..9);
my @lB=1..9;
my @lC="a".."i";

sub trimult{
  my ($l1,$l2,$l3)= @_; #list refs
  my @l; #temp list
  push @l,[$$l1[$_],$$l2[$_],$$l3[$_]] foreach (0..(scalar(@{$l1})-1))
+; #an array of each 3-uplet

  @l=map {$_->[0]}
  sort{$a->[1] <=> $b->[1]}
  map {[$_,$_->[0]]} @l; # S.Transform: sorting according to the first
+ elements (ie array l1)

  my $t=0; # I'm sure there is a perlvar that equals 0 ($| maybe?), bu
+t this aint an obfu contest :)
  ($$l1[$t],$$l2[$t],$$l3[$t++])=@{$_} foreach(@l);
 # so @l is an array of array. So I can cast it's elements type as arr
+ays @{likethis} and the assign them to my vars in a list context.

} #end of procedure

print "@lA, @lB, @lC\n"; #print
&trimult (\@lA,\@lB,\@lC);#sort
print "@lA, @lB, @lC\n"; #print and enjoy.
[download]

Hope you enjoy!

P!