Matlab coder: Multiple coder projects

I have a Matlab function that was used to generate c++ code ten years ago, and this C++ code is included in an existing C++ project. I have a few new Matlab functions that I want to generate C++ code for and include into the same C++ project. I don't want to regenerate code for this old Matlab function, I don't want to touch it at all. But if I generate code for my newest functions and try to include those into the same project I get redefinition errors. Coder allows me to add a namespace for the function I am generating code for, but not for the utility function files like rtwtypes.h so no matter what I do I get redefinition errors for the coder generated types.

The older code was generated column major and the new stuff will be generated row major, and i just don't want to have to go into my C++ project and modify ten year old code. Is there a way to get this done without having to include all Matlab functions in a single Coder project??