Multiple romsets for 1 core?

I’ve learned a lot.from reading on here but I can’t figure this out.

Re-doing my cabinet and trying to incorporate retroarch.

In certain cases. One core is supposed to do several different platforms (pc engine - supergrafx/turbo graphx) etc sega as well?

The only pc engine I see in the core is for supergrafx, how do I also add the rom path for turbographx 16? Can you add a secondary directory for each core or what do you do in this situation?? I’ve run into the same with sega ? (32/mega drive/genesis/master system) etc. How do you direct the core to all of these seperate rom sets??

Hope that makes sense?

Or do I have to take all the roms that a certain core will emulator and put them all together in one folder? Can I still keep them folder sperate? Ie Pc engine ->Pc engine Roms ->Turbographx Roms ->Super grafx roms

Will retro arch go into the sub-folders?? Or how do you guys pull this off, I only want to do this once

I am setting this up for hyperspin in my cab if that helps