are you sure they're not black vultures?
if not, i'm stumped without pics.
Take this advise or not, but do not even dream you thought about shooting a raptor. The fallout is not worth it.
With all due respect are you sure that they are hawks? It seems rather unusual for there to be that many hawks together for an extended period of time.
I used to be into birding and spent alot of nerd time studying hawks....