use List::Compare;
sub elements_found_in_exactly_n_lists {
  my ($n, @array_refs) = @_;
  my $lc = List::Compare->new(@array_refs);
  my @u = $lc->get_union();
  my %h = %{ $lc->are_members_which(\@u) };
  return grep { @{$h{$_}} == $n } keys %h;
}

my @only_two = elements_found_in_exactly_n_lists(
  2, \@array1, \@array2, \@array3,
);