Template function for casting multiple number of params

I'm trying to write a template function that will perform a set of dynamic_casts() based on its template parameter. I've got the following to illustrate:

class FooData
{
public:
    virtual ~FooData() {};
};
class DerivedFooData: public FooData{};
class Other: public FooData{};

void bar(DerivedFooData* d1, DerivedFooData* d2) {}
void bar(DerivedFooData* d1, Other*, DerivedFooData* d2, Other*, Other*) {}


int main()
{
    DerivedFooData d1,d2;
    std::vector<FooData*> container1{&d1, &d2};
    std::vector<FooData*> container2{&d1, &d2};

    // I want bar to be called with container1[0] cast to DerivedFooData and container2[1] cast to DerivedFooData 
    // the first two template params are each container size

    foo<1, 1, DerivedFooData, DerivedFooData>(container, container2);

    // I want bar to be called with
    // container1[0] cast to DerivedFooData
    // container1[1] cast to Other
    // container2[0] cast to DerivedFooData
    // container2[1] cast to Other
    // container2[2] cast to Other
    foo<2, 3, DerivedFooData, Other, DerivedFooData, Other, Other>(container, container2);
}

I can manually create some of those:

template <int N, int M, typename U, typename V>
void foo(const std::vector<FooData*>& input, const std::vector<FooData*>& output) 
{
    bar(dynamic_cast<U*>(input[0]), dynamic_cast<V*>(output[0]));
}

template <int N, int M, typename U, typename V, typename W, typename X, typename Y>
void foo(const std::vector<FooData*>& input, const std::vector<FooData*>& output) 
{
    bar(dynamic_cast<U*>(input[0]), dynamic_cast<V*>(input[1]), dynamic_cast<W*>(output[0]), dynamic_cast<X*>(output[1]), dynamic_cast<Y*>(output[2]));
}

But I can't figure out how to specify in a generic way all combinations of N and M. I assume variadic templates will come in somewhere, but I would need some guidance.