It's not all that impossible. Supposedly the seed companies were working on planters with the ability to switch to multiple varieties instantly on the fly. I had ours set up to do that much much cheaper building my own stuff, but it was more of a quarter mile thing. The idea was for planting refuge corn. Canned the whole experiement and when I got all done ripping it apart the air manifold was full of mouse nest was why I was having so many problems.