Filename1 Item1 - Answer
Filename2 Item1 - Answer
Filename1 Item2 - Answer

##</code><code>##

my %files;
$files{Filename1} = [ 'Item1 - Answer' ];
push @{ $files{Filename1} }, 'Item2 - Answer';
...

##</code><code>##

use strict;
use warnings;
use autodie;

# open the data file for reading
my $data_filename = 'data.txt';
open my $in_fh, '<', $data_filename;

# output files
my $current_filename = '';
my $out_fh;

while (<$in_fh>)    # process one line of data
{
    my ($new_filename, $item) = split ' ', $_, 2;

    if ($new_filename ne $current_filename)
    {
        finalize_table($out_fh) if defined $out_fh;
        open $out_fh, '>',  $new_filename;
        $current_filename = $new_filename;
        initialize_table($out_fh);
    }

    add_row($out_fh, $item);
}

close $in_fh;

finalize_table($out_fh) if defined $out_fh;

sub initialize_table { ... }

sub add_row          { ... }

sub finalize_table
{
    my ($fh) = @_;
    # ...
    close $out_fh;
}