that's right!

'The case for single-stairwell, mid-size multifamily buildings is gaining support in the U.S. Lawmakers in at least 10 states, including California, Oregon, and Washington, have either considered or passed legislation to allow such structures.'

https://www.bdcnetwork.com/multifamily-pro/news/55248122/allowing-single-stairwells-in-multifamily-buildings-could-foster-more-affordable-housing