Implementing a global template function as a member function that accesses members

Question

Disclaimer: I know there are a dozen better ways to implement the following, but I'm doing it as a ways of learning more about templates and pointers to members. I'm playing around with them and I want to see if the following is possible.

I want to have a non-member template function that serves to act as a non-static member function. Different classes can implement it on their own and set which data members the function affects.

template <typename T, typename Y, Y T::* P>
void add10ToMember() {
    *P += static_cast<Y>(10);
}

struct DoubleHolder
{
    double value{ 0.0 };
    void(&add10)(void) =
        add10ToMember<DoubleHolder, double, &DoubleHolder::value>;
};

struct IntHolder
{
    int value{ 0 };
    void(&add10)(void) =
        add10ToMember<IntHolder, int, &IntHolder::value>;
};

In the example I have made the template function add10ToMember, a simple function that adds 10 to the given member.

As soon as I instantiate an object of DoubleHolder or IntHolder, compilation fails and the errors I get are: "'*': illegal on operands of type 'int IntHolder::* '", "'+=': illegal, left operand has type 'int IntHolder::* '".

I understand why I'm getting the error: add10ToMember doesn't actually know which DoubleHolder or IntHolder it should perform the operation on. add10ToMember<IntHolder, int, &IntHolder::value> doesn't become an actual member function; it's still just a global function that has effect on a non-given IntHolder instance.

But I just don't get what the right way to write what I want would be then, if not this. Is it even possible?