Yeah, that's probably the case.
Well, another way would be to change all the assets to some generic stuff (and call it "PharmD. Martin" :) ), and make it very easy to "unlock" Dr. Mario assets by just asking for the different roms supported.
Like, you would just have a button in "Visual and Sounds" called "import ROM", and this would detect which rom you are importing, and extract the music, sounds, and graphics.