use strict;
use warnings;
use Tie::IxHash;
use Data::Dumper;

my %big_hash = (
   'part_1' => tie_me_up(first => 1, second => 2, third => 3),
   'part_2' => tie_me_up(foo => 1, bar => 2, baz => 3),
   'part_3' => tie_me_up(oranges => 1, apples => 2, lemons => 3),
);

print Dumper(\%big_hash);

sub tie_me_up
{
    tie my %temp, 'Tie::IxHash';
    %temp = @_;
    return \%temp;
}

##</code><code>##

$VAR1 = {
          'part_2' => {
                        'foo' => '1',
                        'bar' => '2',
                        'baz' => '3'
                      },
          'part_3' => {
                        'oranges' => '1',
                        'apples' => '2',
                        'lemons' => '3'
                      },
          'part_1' => {
                        'first' => '1',
                        'second' => '2',
                        'third' => '3'
                      }
        };