Multi-beam multiplexing design based on the interleaved subarray architecture can be achieved by uniform linear arrays (ULAs) which only consist of isotropic antennas in previous works. By considering the polarisation information of a signal, the crossed-dipole array is employed, where each antenna is associated with two complex-valued weighting coefficients. To reduce the implementation complexity of the system, when a large number of crossed-dipole antennas are available, we may not need to employ all of them and a subset of the available antennas may be sufficient for a specific beamforming scenario. For this purpose, two design methods are proposed to select the best set of crossed-dipole antennas or dipoles. Designed examples are provided to verify the effectiveness of the proposed methods.