Dwarf galaxies are tracers of the fine-structure of the large-scale structure of the universe, but their predicted abundance and distribution from simulations is in conflict with observations in the Local Group, today's best studied group of galaxies. Recently, two planes of satellites were discovered around Centaurus A, providing a unique opportunity to test cosmological predictions beyond the Local Group. We surveyed the complete Centaurus Group with the Dark Energy Camera, doubling the census of dwarf galaxies in the group. We found evidence that these satellite planes are co-rotating, posing a challenge to LambdaCDM. Comparison with high-resolution dark matter simulations shows that this finding is highly significant. Furthermore, I will connect this to the recently established and unexpected relation between the number of dwarf galaxies and the size of the bulge of the host galaxy in the context of LambdaCDM cosmology and MOND.