Avi K>> This is a hallowed Jewish tradition.
R Berel Wein writes that if there are 100 Jews in a city, Hashem wants to have one shul with 100 people. Jews make 10 shuls with 10 people. Then, as you suggest, we end up with 11 shuls with 9 people. now, R Wein is a Litvish historian, if you can say that, so Hasidim might disagree.
As I understand the halakha, if people truly cannot stand each other, then they should form different shuls.