Polimorphism in std::vector with non-member functions

I have a problem, that I came across. I am working in C++11 with Root, and I have a std::vector which contains variables (histograms) of type TH1D* and TH2D*. I am not allowed to touch the TH1D or TH2D definitions, but I am doing different things based on the type of the variable.

Whenever I want to call an overloaded function, that would handle both cases, my compiler cries out saying "call of overloaded function is ambiguous"... I know it is, but I need help figuring out a better design... How should I do it?

Example:

void save_histograms_from_vector( const std :: vector<TH1*>& histogram_vector_p )
{
    for( auto histogram: histogram_vector_p )
    {
        histogram -> Write();
    }
}
(...)
template<typename TH_type_1, typename TH_type_2, typename TH_type_3, typename TH_type_4> 
void save_as_two_by_two_canvas( TH_type_1 histogram_1_p, TH_type_2 histogram_2_p, TH_type_3 histogram_3_p, TH_type_4 histogram_4_p, TFile* output_file_p, const std :: string& directory_name_p, const std :: string& canvas_name_p, const std :: string& canvas_title_p )
{
     (...)
     const std :: vector<TH1*> histograms = { histogram_1_p, histogram_2_p, histogram_3_p, histogram_4_p };
     save_histograms_from_vector( histograms );
     // This would work if I called the function Write() for each of the histograms )
}

Thank you for all the constructive comments!!