Depends which dynasty. The rebbe reb pinchos dovid had two sons the rebbe reb levi yitzchok and the rebbe reb moshe. The rebbe reb levi yitzchok took over boston while the rebbe reb moshe took over new york. The rebbe reb moshe passed away and left over two sons and to my understanding one became rebbe and one became dayan/rosh yeshivah. I don’t know the new york dynasty too well as I primarily know the grandsons of reb moshe (one is a rov in boro park and one is a rov in lawrence otherwise I don’t know much else). The rebbe reb levi yitchok passed away leaving three sons and a tzavoh that all three should accept the title of admor and in effect create a triumvirate. So in sum total there are four or five bostoner rebbes (as I do believe (but I am not 100% sure) one son of reb moshe became rebbe in beit shemesh while the other stayed in flatbush)
I personally went with the line of the rebbe reb levi yitzchok (it helps that he was the rebbe I went to when I became a bostoner it also helps that I grew up in boston). I do very much hold of the new york dynasty as they do of us. It is a positive mutual working relationship
😀 Zuberman! 😀