template metafunction for detecting template specialisations

Inspired by this question, i'm wondering if there is some compile-time check one can introduce to detect if two given template instantiations:

template <typename T>
class Templ...

typedef Templ<std::string> stringInstance;
typedef Templ<double> doubleInstance;

are constructed from the same definition, or if they are built from different specializations of the Templ template

so basically the hypothetical template function will behave like this:

template <typename T>
class Templ
{}

template <>
class Templ<std::string>
{}

template <>
class Templ<double>
{}

template <typename T1,typename T2>
class Belong_To_Same_Templ_Definition
{}

//tests
typedef Templ<std::string> stringInstance;
typedef Templ<double> doubleInstance;
typedef Templ<int> intInstance;
typedef Templ<char> charInstance;

assert( Belong_To_Same_Templ_Definition< intInstance , charInstance >::value == true);
assert( Belong_To_Same_Templ_Definition< intInstance , doubleInstance >::value == false);
assert( Belong_To_Same_Templ_Definition< stringInstance , doubleInstance >::value == false);

is possible to create this kind of metafunction?