Not sure if this can help you...

#!/usr/bin/perl

use strict;

my $file_1 = <<EOF;
0001Hadrian
0002Claudius
0003Julian
0004Augustus
0005Severus
0006Constantine
0007Valentinian
EOF

my (%record, $count_line);
my $page_number = 1;

open( my $fh, "<", \$file_1 )
  or die "Could not open file.\n";

while (<$fh>) {
    chomp;
    s/(\d{4})//;
    $record{$1}->{$_}->{'Master'}++;
}
close( $fh );

while (<DATA>) {
    chomp;
    s/(\d{4})//;
    $record{$1}->{$_}->{'Child'}++;
}

for my $i ( sort keys %record ) {
    for my $j ( sort keys %{ $record{$i} } ) {
        if ( defined( $record{$i}->{$j}->{'Master'} ) ) {
            print "\t\t\t$j\n";
        }
        else {
            print "$j\n";
        }

        $count_line++;
        if ( $count_line == 5 ) {
            print "\n\t\tPage is $page_number\n\n";
            $page_number++;
            $count_line = 0;
        }
    }
}


__DATA__
0001Legio IX
0001Legio VI
0001Ursa Minor
0002Veraculum
0002Thrace
0002Legio III
0003Persia
0003Londinium
0004Legio II
0005Caledonia
0005York
0006Christianity
0006Constantinople
0006Legio II
0007Julian
0007Legio VII
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