One priest in the diocese who was trying to merge two Catholic churches for numerous Sundays
spoke of One Faith community.
I believe that some people wanted their Catholic church and only their Catholic church.
The Creed says One Holy Catholic Church.
I don't really know if it is necessary to join multiple parishes under one priest, each parish is it's own community and is lead by the head pastor of each parish. Insular Catholicism has always been an issue but the Catholic Church is an evangelistic Church that must preach the Gospel and save souls for the glory of God.