Can a landlord divvy up heating by building as opposed to individual units?

I can not think of any law or any reason this is not legal if it is spelled out in the lease, because you do not have to rent the unit. Unfair is not the same as illegal. A bigger concern would be the maintenance of the heating equipment and the price of heat in general. Does the landlord maintain the heating systems or are they old and not working properly meaning higher heating bills; and what happens when the cost of heat increases, does the landlord increase his share or leave it all on the tenants. I would rent somewhere else.