You Mixed that up.
In your WorldFolder, is a:
That contains all the settings that affect the whole World and also the Biomes that get Generated.
This Folder Contains various *,bc files. Each file contains the Settings for the Biome of the same name. Currently it should host all default Biomes. If you delete one there, it will just be generated anew.
This Folder serves the same Purpose as the GlobalObjects folder. Just, only for that specific World, here go the Objects for the World.
The BiomeGroups the Guide mentiones are inside the WorldConfig.ini