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

my @ary_of_hrefs = ({id_1=>'A',id_2=>'B'},{id_1=>'V',id_2=>'Z'});
my %hash = map { delete $_->{id_1} => { delete $_->{id_2} => $_ } } @a
+ry_of_hrefs;

print Dumper \%hash;

my $hash;
foreach my $href ({id_1=>'A',id_2=>'B'},{id_1=>'V',id_2=>'Z'}) {
    my $id_1 = delete $href->{id_1};
    my $id_2 = delete $href->{id_2};
    $hash->{$id_1}->{$id_2} = $href;
}

print Dumper \$hash;

__output__
$VAR1 = {
          'A' => {
                   'B' => {}
                 },
          'V' => {
                   'Z' => {}
                 }
        };
$VAR1 = \{
            'A' => {
                     'B' => {}
                   },
            'V' => {
                     'Z' => {}
                   }
          };
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