The parcels are held for strategic reasons, to ensure that they can be set for sale to people who hold the right political color.The price for a couple of them is unprecedently high, too high for anyone to purchase them spontaneously, and the owners admonish anyone who is interested in the parcel to contact the owner for a discussion of the price. The reason is obviously to be able to choose who can buy it.
I ask the RA to consider a way to prevent this kind of thing by implementing a law. But to be honest I suspect that it is impossible. It can probably only be solved through a peace treaty...