There has recently been demonstrated experimentally that a bimetallic particle dimer composed of gold and silver atoms may work as a directional frequency filter which scatters light of different frequencies in different directions [T. Shegai, et al. "A bimetallic nanoantenna for directional colour routing", Nature Commun. 481 (2011)]. In this presentation, we determine how a system composed of two nonidentical two-level atoms could work as a nano-antenna for light routing or as a directional frequency filter for emitting light of different frequencies in different directions. We calculate the radiation pattern of the emitted field intensity and detected in a far-field zone of the radiating system. The calculations include direct interatomic interactions and arbitrary linear dimensions of the system. We find that the radiation pattern is not spherically symmetric and the degree of the asymmetry depends strongly on the distance between the atoms and the Rabi frequency of the driving field. We have established the clear connection between the frequency routing and the coherence between the symmetric and antisymmetric states of the system.