Just have the zerg add them to the hive, then. End of problem!
Seriously, while it's a shame about the cerebrates (maybe Blizzard and GW can work out something so you folks can bring them back in SC3?), it's great that both companies are trying not to step on each others' collective toes. Wish more companies would get along nicely like that, actually.
Then again, a Tyranid Cerebrate is not something I want to think about too much...