my %hash = map {split} <DATA>;

for my $key ( map { $_->[0] }
              sort custom_sort
              map {[ $_, $hash{$_} =~ /([A-Z]*)(\d+|[A-Z]+)/ig ]} keys %hash) {
    print "Key = $key, Value = $hash{$key}\n";
}

sub custom_sort {
   my $i = 1;
   for (;;) {
        return -1 unless defined $a->[$i];
        return  1 unless defined $b->[$i];
        my $c = $a->[$i] cmp $b->[$i] || $a->[$i+1] <=> $b->[$i+1];
        return $c if $c;
        $i += 2;
   }
}

__DATA__
a 2
b 1
c 12
d a12
e a9
f a2b3
g a2b4
h b2b4
i 12
j a2bb5
k a2bb5a
l a2bb5b