The problem of metrological standards development for aspherical wavefronts is discussed. A method for aspherical wavefront shaping by means of combined (or twin, multiplexed) computer generated hologram (CCGH) is presented. The CCGH reconstructs two wavefronts: the first one is used for calibration of the second one by means of a Fizeau interferometer and a highly reflective flat reference surface. Different CCGH encoding methods are discussed. The design of a CCGH with subaperture division in the shape of angular sectors is presented. The absence of cross-talk errors in both wavefronts was demonstrated experimentally.