The option list to be split into parts
The list of option lists whose keys are used to break up the original options into separate pieces.
The option lists taken from the original based on the keys of the other objects. The first one in the list consists of the values not appearing in any of the others (i.e., whose keys were not in any of the others).
Separate options into sets: the ones having the same keys as the second object, the third object, etc, and the ones that don't. (Used to separate an option list into the options needed for several subobjects.)