Hmmmm....
Where I live there are MANY homes with only one kitchen, and possibly one bathroom, but with multiple families living within! This is in a neighborhood that is zoned "single family" by village code.
My neighbor has a very old travel trailer permanently parked on his property and he once had 4 adults and 4 children living in it - until I asked Family Welfare to check them out. Various people continue to circulate within the main residence, which doesn't bother me since they likely have better living conditions than in that small cramped travel trailer.