Some native New Yorkers' dream came true on the Fifth Avenue sidewalk between East 22nd and 23rd streets yesterday. An unknown person had divided the sidewalk with a white line: one side for tourists and the other marked "New Yorkers." Receptionist Bianca Smith said she liked the idea. "New York tourists are annoying. They stop, look around, take pictures, and hold me up. I don't know if the lanes could be enforced, but it would be nice. For now, I'll just keep walking around them," she said.