Reduce .c and .h files for code generation with referenced models

I have a Simulink project with many referenced models, e.g.

When I generate code, I get for each .mdl one .c and three .h files, what result in many files.

Is it possible to reduce the number of files, e.g. only one .c and one (or three) .h file/s ?

PS: We work with referenced models (and not subsystems) because multiple persons can work together then.