It may surprise you to know that in the US as a ham, I have the legal right to hoist an antenna or build a tower so long as it doesn’t fall on a power line.
But even then, I don’t think this setup will create nulls. Say the antenna is 400 meters away which I think is still in the far field but I could be wrong. Even if I erected an almost resonant tower (160m) and assuming the regulatory bodies gave me the permit to do so, assuming it’s not powered and simply is resonant, maybe the radiation pattern changes but not so dramatically that my neighbors on the opposite side of my antenna (from the tower) will get poor reception.
Is the direction of the radiation pattern changing what was meant by the “not-spots”?