If one owner rents half of a house, is the contract valid?

Primary text

If one owner rents half of a house, the contract is valid because delivery of that half is possible. If he subsequently rents the other half to the first renter, it is valid because delivery is possible to him. If he rents the other half to a different person, there are two views, depending on the ruling regarding renting an undivided share to a non-partner, as delivery of what was rented to the second party becomes impossible.