The Greys' Hive is a drone matrix created by the Greys which spans from their home planet to inhabited planets orbiting around red dwarf stars all across 5 galaxies(6 if you include a small proto-galaxy). It is what unifies most of the Grey species as a whole. It operates on FTL transmissions, including tachyonic, sub-space and hyperspace transmissions. It is also the main source of power that allows their saucer ships to create artificial wormholes across the fabric of space and time. Occasionally, Sub-Grey species would disconnect themselves from this collective, and that wasn't always good for the Greys or for other species.