Laser light sources are routinely applied building blocks in optical sensor technologies. While lasers are emitting at a precisely defined wavelength within narrow emission bands, chem/bio-sensing applications frequently demand multi-wavelength illumination for addressing a series of species. Instead of using broadband radiation sources, it is a viable strategy to efficiently combine the beams emitted from different lasers to maintain the spectral brightness and yet cover extended wavelength regimes. In this study, substrate-integrated hollow waveguides (iHWGs) are reported as a versatile and efficient alternative compared to conventional beam combining concepts, especially for applications in the mid-infrared spectral regime leading to a highly efficient multi-port beam combiner-the iBEAM.