my %firstDataSet;
foreach (my $line = <FIRST_FILE>) {
    my @data = split /\s+/, $line;
    $hash{$data[0]}{$data[1]} = $data[2];
}

foreach (my $line = <SECOND_FILE>) {
    my @data = split /\s+/, $line;
    if ($hash{$data[0]}{$data[1]}) {
        print OUT_FILE "$data[0] $data[1] $hash{$data[0]}{$data[1]} $data[2]\n";
    }
}