Another recursive solution using a subroutine that takes a block of code to execute against a "chunked" list.

use strict;
use warnings;

use 5.010;

sub groupsOf (&$@);

my @list = ( q{a} .. q{z} );

say for groupsOf { qq{@_,} } 5, @list;
say for groupsOf { qq{@_,} } 7, @list;

sub groupsOf (&$@)
{
    my $rcToRun  = shift;
    my $groupsOf = shift;

    my $rcDoIt;
    $rcDoIt = sub
       {
           $rcToRun->(
              map shift, 1 .. ( @_ < $groupsOf ? @_ : $groupsOf )
              ),
           @_ ? &$rcDoIt : ();
       };

    &$rcDoIt;
}
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I hope this is of interest.

Update: Oops, forgot to post the output :-(

a b c d e,
f g h i j,
k l m n o,
p q r s t,
u v w x y,
z,
a b c d e f g,
h i j k l m n,
o p q r s t u,
v w x y z,
[download]