To dynamically create arrays, just create an array of arrays. See perldsc - Perl Data Structures Cookbook and perllol - Manipulating Arrays of Arrays in Perl for details.

#!/usr/bin/perl
use warnings;
use strict;

use Data::Dumper;

my @arrays;
my $count = -1;
while (<DATA>) {
    chomp;
    $count++ if $_ eq '[';
    next if /[][]/;
    push @{ $arrays[$count] }, $_;
}

print Dumper \@arrays;

__DATA__
[
aaaa
bbbbb
]
[
ccc
dddd
eeeee
]
[
f
]
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