My sewing room is in the lower level of our house in a bedroom. The closet had a door that opened into the closet, which was really awkward. You had to go into the closet and close the door to access what was behind the door! I found a curtain made of strings, like soutache braid or fine cording. It allows easy access to the closet while still creating a barrier, both visual and physical. Maybe something like this would accomplish what you want.
Leslie