At the outpost of Montefiore Medical Center, there exists what is believed to be the only legal-medical partnership in the country designed specifically for children who crossed the Mexican border illegally and are trying to settle into their new communities. Known as Terra Firma, the program began in October 2013, months before the surge of unaccompanied minors entering the United States.

While immigrants’ advocates have consistently deplored the dearth of lawyers to meet the needs of the new arrivals, their focus is now shifting: It has become clear to lawyers and advocates alike that mental health services with Spanish-speaking therapists are also desperately lacking.

Terra Firma is still limited in scope, having served about 200 children in three years, but it has defined a holistic model that other legal service groups in New York say they would like to adopt. “There’s a lot of needs the kids have outside the legal ones,” said Brett Stark, 30, a lawyer for Catholic Charities New York and one of the three founders of Terra Firma. “For them to participate meaningfully in their own case, they have to be empowered and enabled by doctors and psychologists.”

There are other legal agencies in New York that provide mental health services for immigrant youth, including the Door and the Safe Passage Project, but none with a distinct legal-medical partnership for unaccompanied minors.

Because Terra Firma is the only place offering such services, groups are considering opening similar programs in Queens or Brooklyn. “At least we have started the conversation,” Mr. Annobil said. Although Terra Firma offers individual counseling and medical appointments for children and their guardians, the heart of the program is its 10-month group therapy unit. To foster closeness, it is restricted to 12 girls and 12 boys, who meet on alternate Wednesdays.

The participants come for dinner first, and then take part in the Zumba class taught by Deborah Snider, the associate director of community pediatric programs for Montefiore Medical Center. “When people walk into the clinic and see a meal prepared and Zumba, they think, ‘Wow, they treat us like human beings, like people,’ ” Dr. Shapiro, 56, said.

After Zumba, the teenagers gather in a conference room. Dr. Muñiz, 34, and a social worker use games and guest speakers to stimulate group discussion on trauma, from sexual assault to gang violence, and help the children cope with their emotions. The night concludes with a meditation and mindfulness exercise called “la balanza.”

The Children’s Health Fund, a national nonprofit agency that operates mobile medical units for homeless youth, helped found Terra Firma and operates the clinic’s base in the Bronx. With the agency’s financial support Terra Firma expanded programming to include summer English classes, soccer and a five-week photography class.