partial template specialization for friend classes?

I have a simple class X, and set of templatized classes Y<T,U>. I'd like all classes Y where the first templatization parameter happens to be X to be a friend of X itself. The following hopefully conveys what I want, but the friend statement gives a compile error.

template<typename T, typename U>
class Y {
};

class X {
    public:
        X(int value) : i(value) {}
        const int& getI()    const { return i; }
    private:
        int    i;
        template<class U> friend class Y<X,U>;
};

I'm not sure templatization of friend statements is allowed at all (let alone partial templatization of friend statements). Is there a way to do this? Or am I stuck listing out all the friends one-by-one?

Thanks, Matt