c++11: dispatch arguments between base classes upon construction

Assume one has a class derived from two base classes.

class Derived : public Base1, public Base2 {
};

In order to instantiate/construct an object of type Derived my initial idea was to use parameter pack. The problem is that I do not know how to dispatch arguments between Base1 and Base2 respectively.

template <typename... TArgs>
Derived(TArgs&&... args)
  : Base1(/* what goes here? */)
  , Base2(/* what goes here? */) {
}

I know in advance that Derived inherits from only two base classes. My question is whether one has a way construct derived with a syntax similar to the below?

Derived d({arguments for Base1}, {arguments for Base2});

template <typename T1, typename T2>
Derived : Base1(T1), Base2(T2) {}

And if possible then what would be the requirements for the Base classes?

How should they accept they construction arguments?