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This story was originally published by Chalkbeat. This is part two of a three-part series. Here’s the first story . And sign up for Chalkbeat New York’s free email newsletter to be the first to know when the next story is published.

As a parent leader for more than a decade, Johanna Bjorken has heard plenty of stories about New York City schools struggling with low enrollment.

But Chalkbeat’s investigation last month into the decline of Murry Bergtraum High School for Business Careers — the city’s smallest traditional high school with roughly 90 students — struck a nerve.

Bjorken’s son goes to school just two floors above Murry Bergtraum in a shared building in Lower Manhattan where the students play on joint sports teams. Yet the schools feel worlds apart. While Bjorken’s son takes Advanced Placement Calculus, students at Murry Bergtraum last year had only one math teacher and two math courses , Algebra I and II. Despite having a per-student budget nearly twice the city average , Murry Bergtraum’s limited academic offerings force some students to attend night school to graduate.

“I was shocked to hear that students, some of whom may very well play volleyball or soccer with my child, have to go to night school for basic graduation requirements, and moreover, that the school’s situation has been known for many years with no action,” Bjorken wrote in a September letter to city officials.

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Like school districts across the country, New York City is struggling with a small schools crisis after years of enrollment declines. What makes the city’s situation unique, however, is how many of its small high schools share buildings with each other: 72 of the city’s high schools with fewer than 250 students are on shared campuses, a Chalkbeat analysis found.

Ten months into his tenure, pressure is mounting on New York City Schools Chancellor Kamar Samuels to address the increasing number of small schools, which cluster the most vulnerable students in schools with the fewest academic opportunities. School leaders and experts say that long term, the city will need to close and merge underenrolled schools — a process that can be slow and politically unpopular. But many principals feel they can’t afford to wait for that process to play out and feel a sense of urgency to ensure their current students have access to high-quality programs and advanced courses. Now, a growing chorus is urging Samuels to help small schools on shared campuses pool their resources.

“On shared campuses like ours the system accidentally pits us against each other — right when we need to share resources the most,” said Amy Piller, the principal of Urban Assembly Maker Academy, the school Bjorken’s son attends on the Murry Bergtraum campus.

Samuels indicated at a town hall last week that he’s not crafting a citywide plan and instead is asking five working groups to devise blueprints for underenrolled schools in their districts. None of those working groups includes high schools, but Samuels told parent leaders this week that the Education Department is looking at creating “campus working groups” for high schools. City officials have not shared a timeline for this work. An Education Department spokesperson did not respond to questions about how, or whether, the city is helping schools in the same building share resources.

In the meantime, some principals on shared campuses have pooled course offerings, while others have not — but are looking for guidance and support from the Education Department as they’ve seen their rosters shrink.

“They kind of leave principals up to their own devices,” said Mike Sill, the secretary of the United Federation of Teachers.

About two decades ago, the Bloomberg administration made a big bet that small schools would better serve vulnerable students by providing them with more individual attention and ensuring they didn’t slip through the cracks. The city shuttered dozens of troubled large high schools and opened scores of small new ones in their buildings.

Small schools boosted graduation rates and college enrollment , but they couldn’t provide the same variety of extracurricular or academic options as larger schools.