How to assign discount, shipping method & payment method to "all except"?

[SteP[IT]]

I'm in the needing of assign both discounts rules, shipping methods and payments methods in a way that currently seem not to be possible...

For example, I need to assign one specific discount to a nation, and another one "to all nations except the one" I assigned the previous mentioned discount.
I have to do the same both for shipping and payment.
This is why, for example, I have to set a basic discount for my Country, and a higher one for all the other countries (=all except my one)

But, as far as I can see,  it seems it can't be done now without hacking the core...

Is there a simple way to get that? Could it be eventually placed in the "ask for enhancement" requests queue?

Thank you in advance

[SteP[IT]]

Any hint about this question? regards