Adding functions into class but avoid recompilation

Currently I have a

//ModelFac.h Class ModelFac: public Singleton <ModelFac>{ public: int CreateModelA (a list of arguments); int CreateModelB (another list of arguments);// CreateModelA and CreateModelB have different function implementations };

When I want to call functions, I will call ModelFac::Instance().CreateModelA(args). Those functions are being called in different .cc files. However when I add new CreateModelC function, all files that calls ModelFac::Instance().CreateModelX(different args) will need to be recompiled since they all include ModelFac.h, which is really time consuming.

Can I somehow fix this situaion but still leave ModelFac::Instance().CreateModelA(args) this type of call format for implementation?

I don't want to make different classes for different CreateModel functions, which will cause a lot fixes in the whole program. It will be greate if I can still use ModelFac::Instance() but then pass CreateModelA as the first argument.

Thanks.