From Merriam Webster
balkanize
verb, often capitalized
bal·kan·ize | \ ˈbȯl-kə-ˌnīz \
balkanized; balkanizing
Definition of balkanize
transitive verb
1: to break up (a region, a group, etc.) into smaller and often hostile units.
2: DIVIDE, COMPARTMENTALIZE, now pop culture has been balkanized; it is full of niches, with different groups watching and playing their own things— Richard Corliss