This is my take on your problem using split twice with array of anonymous arrays.

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

my @strings;

while (<DATA>) {
        #  Split up input stream using dashes
        my @smallarray = split '-';     #  @smallarray now has 'aaa bb
+b ccc', etc.

        #  Iterate through @smallarray items and split them up using s
+paces
        #  Create an array of anonymous array references
        #  The references are the array resulting from split, using []
        push(@strings, [split /\s/]) foreach (@smallarray);
}
[download]

#       The array of anonymous arrays now looks like this:
#
#       $VAR1 = [
#                       'aaa',
#                       'bbb',
#                       'ccc'
#               ];
#       $VAR2 = [
#                       'ddd',
#                       'eee',
#                       'fff'
#               ];
#       $VAR3 = [
#                       'ggg',
#                       'hhh',
#                       'iii'
#               ];
#       $VAR4 = [
#                       'jjj',
#                       'kkk',
#                       'lll'
#               ];
[download]

#  Print out the whole AoA contents
foreach my $arrayref (@strings) {
        print "$_\n" foreach @$arrayref;
}

print "----\n\n";

#  Or just the contents of one group
foreach my $item (@{$strings[0]}) {
        print "$item\n";
}

__DATA__
aaa bbb ccc-ddd eee fff-ggg hhh iii-jjj kkk lll-

__OUTPUT__
aaa
bbb
ccc
ddd
eee
fff
ggg
hhh
iii
jjj
kkk
lll
----

aaa
bbb
ccc
[download]

--
Allolex

Perl and Linguistics
http://world.std.com/~swmcd/steven/perl/linguistics.html
http://www.linuxjournal.com/article.php?sid=3394
http://www.wall.org/~larry/keynote/keynote.html