`RentIncomeMember` MUST be equal to the summation of the underlying children members.
`RentalIncome` MUST exist at least once.
`RentalIncome` MUST exist at least once.
`RentalIncome` MUST exist at least once.
`RentalIncome` MUST exist at least once.
`RentalIncome` MUST exist at least once.
`RentalIncome` MUST exist at least once.
`RentalIncome` MUST exist at least once.