Unless it changed this period you don't need 3 people.Last period we did it with 2 people and I think you can even do it alone.Only reason to go in a group is security.
btw, lil offtop, about brahmins in bases Well, brahmins don't respawn anymore atm, after getting killed. One of my enslaved merc has pwned some brahmins, after then get pwned himself.I'am getted enslave some of them, to compensate for losses. How could I can transform em to normal brahmins, attached to a base?