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;
}