use strict;
use warnings;
use Data::Dumper;

my %hash;

my @array1 = qw( one two three );
my @array2 = qw( four five six );
my @array3 = qw( seven eight nine );

add_arrayref_to_hashref( \@array1, \%hash, 'key1' );
print "\nafter adding array1 using key1:\n", Dumper( \%hash );

add_arrayref_to_hashref( \@array2, \%hash, 'key1' );
print "\nafter adding array2 using key1:\n", Dumper( \%hash );

# getting a bit fancier here...
my $array3ref = \@array3;
add_arrayref_to_hashref( $array3ref, \%hash, ${ $array3ref }[1] );
print "\nafter adding array3 using ${ $array3ref }[1]:\n", Dumper( \%hash );

sub add_arrayref_to_hashref
{
	my ( $arrayref, $hashref, $key ) = @_;

	push( @{ ${ $hashref }{$key} }, $arrayref );
}