Im not quite sure what you are wanting to end up with but try this: 
use strict;
use warnings;

my @array = qw(
  1nkndnfd
  2nsnskdnsdn
  3ddjsjd
  4fksjsdj
  5kdsjdskjdskj
  1ksdjdjsk
  hg
  2dsjskj
  3djkdjsljs
  4fdkkjdskjsk
  5sadjjdjdodjs
  6sadjjdjdodjs
);

foreach (@array) {
    my ( $num, $data ) = /(\d)(.*)/;
    next if ( !length $num || !length $data || $num !~ /[1-5]/ );
    open my $file, '+>>', "round_robin_$num" . ".txt";
    print $file "$num - $data\n";
}

[download]
EDIT: Just noticed other replies, looks this is NOT what he/she was after.

In reply to Re: Splitting a Blocked file in Round Robin into smaller files by james28909
in thread Splitting a Blocked file in Round Robin into smaller files by tradersjoe0

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