He is buying a group that already has that infrastructure. One purchase, and he can fold his tiny group into theirs now.
My experience, in multiple businesses, is that rarely happens. When Company A buys Company B, it keeps its people and throws Company B's out. It only keeps the other's people if they perform a function it doesn't already have, and performance won't save anybody.
If Warshaw is smart, he will keep Alpha's HR department, but I'll believe it when I see it. HR is also usually one of the first departments "consolidated" when new owners take over.