sub custom_sort {
    my @a_parts = split /,/, $a;
    my @b_parts = split /,/, $b;
    return $a_parts[0] cmp $b_parts[0] ||
           $a_parts[1] cmp $b_parts[1] ||
           $a_parts[2] cmp $b_parts[2];
}

# To invoke:
my @sorted = sort custom_sort @{ $outputRef };