Romcenter

Is this the way not to let RomCenter check/fix those "merged" rom?

Like this:
a.zip is the main rom-sets, a1.zip, a2.zip are the alternate rom-sets.
So, a1.zip & a2.zip need some of the files in a.zip in order to run.

In RomCenter, is it possible a1.zip & a2.zip contain only roms that are not available in a.zip? So that it wouldn't be listed in the Fix part (showing that "rom available" etc, not showing these, imho, easier to manage split-rom......)

Thanks in advance.

Yes. In the preferences under romsets check the "split" radio button. That way only the roms specific for that set are in the ZIP. I believe that you have to set this per DAT file.

HTH