How to resource one *.h map file to support two separate CHM files?

Can somebody assist me in understanding how to manage/edit "one" *.h map file in order to support two separate help systems for one application?

I've developed two "separate, but identical" Robo8 projects (Metric vs US Units) for one engineering product. One application program is International and the other Domestic. The program developer wants to use a single *.h map file with resources mapped correctly for both XXX_India.chm and XXX_US.chm files.Therefore, when she indexes (include only one XXX_.h file with a single resource definition) the US chm file, she can start with the current XXX_India.h file, not change anything from the current content (that maps the current resources for India chm) and any changes that should be made for US can be made at the end of the existing *.h file, without touching at all the previous India content?

Is this proposed editing of the *.h map file manageable in order to accomplish a single .h file for two separate product help systems? If so, what all is involved in creating this dual resource *.h map file?

Any assistance with this question is greatly appreciated.

Thanks.