[CMake] Xcode: Nested Xcode Projects

[Matthias Dörfelt]

Hi,

I am currently generating sub projects with cmake using the add_subdirectory command together with the Xcode generator. It works, but the top level Xcode project includes the sources and targets of all the sub projects. Is it possible to make it reference the actual Xcode sub projects instead(to get closer to a "normal" Xcode workflow)? 
If it's not possible with current CMake it would certainly be a very neat addition!

Thanks