We have presented the excitonic configuration interaction (ECI) method for the calculation of electronic states of multichromophoric systems. It is based on an excitonic approach, i.e., it is essentially a variational calculation in the basis of antisymmetrized products of site states, but including not only ground-state (GS) and local-excitation (LE) products, but also multilocal-excitation (MLE) products. The Hamiltonian matrix is evaluated withing McWeeny's group function theory (GFT). We also present a systematic approach to include embedding via arbitrary point charges (APCs) in the sitestate calculations, either in a self-consistent way (EHF, excitonic Hartree-Fock) or using point charges obtained from fitting the electrostatic potential (ESP); these are to be contrasted from the frozen-density approximation (FDA).