A generalized bipolariton model is proposed. In this model a biexciton is formed from virtual excitons of four kinds. There exists both attractive and repulsive interaction between these excitons, though only excitons of a specific type can interact with light. In the framework of this model a closed set of nonlinear equations for macroscopic amplitudes of interacting coherent photons, excitons, and biexcitons was obtained. Its difference from the analogous set of equations obtained earlier [1,2] for a simpler model [3,4] when only two kinds of excitons are present and each of them can interact with light. A substantial difference between these models is shown for the case of nonlinear transmission/reflection of ultrashort laser pulses by a thin semiconductor film under two-photon generation of biexcitons. The numerical solutions of the macroscopic equations are found for various values of the film thickness, detuning from the two-photon resonance, laser pulse duration, and intensity. It is shown that the thin film substantially transforms the incident pulse. At specific conditions high and narrow transmission and reflection peaks can appear, or even trains of such peaks. In some cases their height can considerably exceed the amplitude of the incident pulse. The results obtained in the generalized bipolariton model for nonlinear transmission/reflection of ultrashort laser pulses by a thin semiconductor film are also compared with the analogous results obtained in the framework of simpler phenomenological models [5-8].