Co-working startup Grind is planning to close its Garment District location this month and is negotiating to give the space back to its landlord, which last year opened its own competing shared-office location in the building, sources told The Real Deal. Grind is in discussions with Charles Aini and Isaac Chetrit, the owners of 1412 Broadway, to terminate the roughly 14,000-square-foot lease the company holds in the 24-story building at West 39th Street, multiple sources told TRD.