physical chemistry - Hierarchy of electronic wavefunctions

The previous question contained too much unnecessary information and was edited.

I am wondering about the "hierarchy" of wavefunctions. If one can combine atomic orbitals (AO) into molecular orbitals (MO) through the LCAO method, could one combine MOs to form a supra wavefunction, or an LCMO?

I've done some research and found a paper on an approach to finding the MO of molecules by effectively taking a LCMO of smaller molecules or constituents. While interesting, this is not what I'm referring to as a "supra" wavefunction, if there's such a thing.