Nothing is certain and nothing can be taken for granted. You can introduce a few with apparently not much aggression and suddenly a seemingly docile angel can react violently to one particular angel. Rockwork may save it from being killed, but if the aggression is unrelenting, this will stressed the new angel and in time, it may succumb to parasites/diseases. Introducing increasingly bigger fishes may deter potential bullies and certainly bigger tanks of at least 7 feet would be good.
That said, you can certainly succeed with a few large angels in the same tank. I have done it and was beginning to think that aggression was an overexaggeration until I added an emperor to which my blueface immediately attacked and this carried on for weeks until it died. The blueface was previously almost nonchalant when 4 other species of Angels were introduced into the tank(at different times). It also cohabited peacefully with an Emperor which had been with me for over 3 years, and which had died earlier from an infection.
So as you can see, it has more to do with luck and the particular specimen you have. Everything else is no guarantee.