Renting a house on a 6 acre plot

[Chris Allen]

I am going to try and explain my question well, but bear with me.

My parents and I split a 12 acre plot of land.  I built on 6 and they built on 6.  If my mother eventually either passes or moves in with me in her advanced years, I am considering renting her house as my Dad passed last year.  

In the county we built in, 5 acres is the minimum plot size so I cannot split the land at all until legislation/zoning changes.  I would like to have access to as much of the land as possible though in the future.  As a landlord, do I have to provide as part of the lease the entire 6 acres of my mom's land to a renter since that is part of the property of the houseand cannot be subdivided?  Or, can I indicate that the house and an acre of land is part of the rental agreement, and the additional 5 acres is still in my control?