City Girls: The Nisei Social World in Los Angeles: 1920-1950 by historian Valerie J. Matsumoto tells the story of countless young Nisei — second-generation Japanese-Americans — pursuing their interests in ethnically based social and recreational clubs.
“So many of the ethnic youth clubs formed because the Nisei didn’t always feel welcome in school, community and church groups,” Matsumoto said. “But these girls wanted to participate in activities and have fun. The clubs were really important in helping them find a place of belonging.”
Matsumoto spent 20 years interviewing Nisei for her book. At its peak, there were 400-600 youth groups in the Japanese American community.
You can gain more insight into these groups in this story from UCLA.