Well, I think it's safe to say that our Thalan friends might have access to a *limited* collective consciousness rather than a true "hive mind." Perhaps they can share experiences via direct contact a la Heinlein's "Puppet Masters." Or maybe it's more like StarCraft's Zerg, where each planet in the "Hive" is run by its own "queen" with some form of independent identity (that would explain elections and morale issues.)
Honestly, the only true "hive mind" I've seen that came close to holding water is the Tyranid race in WH40K, and that's because their collective consciousness extends through the psychic medium of warpspace. GC doesn't allow for "dimensions of thought" or similar constructs, to my knowledge, so actually maintaining a unified intelligence across the interstellar void would be absolutely impossible.