Transfer of property to spouse

Hello Experts,

Need suggestion for better tax planning. My mother is a senior citizen aged above 67 and having a rental income amounting 15 lacs annually. My father is also senior citizen aged above 75 is not having any income. The rental income is from same property having two different floors on it. Since the mother is the sole beneficiary of the rental income of this amount her annual tax falls beyond 30% tax category. Is there are way to transfer the one floor rental income to fathers name or anyone in family so that that the income can be divided and avail the tax benefit. Or if there is any other way to manage this income so that minimum tax can be paid.

Thanks in advance.

Rajiv