We propose a methodology for the realistic simulation and prediction of resonance energy transfer in condensed phases based on a combination of computer simulations of phase morphologies and of a distributed monopole model for the radiationless transfer. The heavy computational demands of the method are moderated by the introduction of a transition charges reduction scheme, originally developed for ground state interactions [Berardi, R. et al. Chem. Phys. Lett. 2004, 389, 373]. We demonstrate the scheme for a condensed glass phase formed by perylene monoimide end-capped 9,9-(di n,n)octylfluorene trimers, recently studied as light-harvesting materials, where we couple a coarse-grained Monte Carlo simulation of the molecular organization and a master equation approach modeling the energy diffusion process.