my @l = ({FN => 'Les', LN => 'Howard'},
	 {FN => 'Larry', LN => 'Wall'},
	 {FN => 'Randal', LN => 'Schwartz'});

my @sorted = map { $_->[2] }
             sort { $a->[1] cmp $b->[1] || $a->[0] cmp $b->[0] }
             map { [$_->{FN}, $_->{LN}, $_] } @l;

foreach (@sorted) {
    print "$_->{LN}, $_->{FN}\n";
}