Is there a way to calculate shared expenses in owner occupied income properties

smokeysf

My home has been split into an ADU. I pay and then bill back utilities based on a fixed percentage (squarefeet). I am also depreciating the property that way. Is there a way to automatically split the billing? Is the best way to set up the rental unit as a seperate address or as a sinlge address with two tenants one paying, one not paying(me)?