my %subhash = %{ $hash->{'Key1:Key1_si'} };
my @sorted_keys = sort { $subhash{$a}{keyc} <=> $subhash{$b}{keyc} }
                       keys %subhash;
for my $key (@sorted_keys) {
    print "Key1:Key1_si $key";
    print ' ', $subhash{$key}{$_} for sort keys %{ $subhash{$key} };
    print "\n";
}