[nznog] spam farms

Is there anything that can be done about these 'Spam Farms' ? ie Companies that take 30+ C classes have a domain for every c class and set up reverse and forward mx<num>@<domain> for each ip. They appear to be designed purely for spam and One company in particular ive been having issues with, appear to own a couple hundred C class. Is there any way they can be mass listed with spam servers? Liz Q