  We report the discovery that substructures/subhaloes of a galaxy-size halo
tend to fall in together in groups in cosmological simulations, something that
may explain the oddity of the MW satellite distribution. The original
clustering at the time of infall is still discernible in the angular momenta of
the subhaloes even for events which took place up to eight Gyrs ago, $z \sim
1$. This phenomenon appears to be rather common since at least 1/3 of the
present-day subhaloes have fallen in groups in our simulations. Hence, this may
well explain the Lynden-Bell & Lynden-Bell ghostly streams. We have also found
that the probability of building up a flattened distribution similar to the MW
satellites is as high as $\sim 80%$ if the MW satellites were from only one
group and $\sim 20%$ when five groups are involved. Therefore, we conclude that
the `peculiar' distribution of satellites around the MW can be expected with
the CDM structure formation theory. This non-random assignment of satellites to
subhaloes implies an environmental dependence on whether these low-mass objects
are able to form stars, possibly related to the nature of reionization in the
early Universe.
