not sure about 5-6 inches. But 3 is doable. Just have the object as two models and print the right side with the right nozzle and the left side with the left nozzle.
You'll also need a slicer that lets you change the build plate dimensions. Simplify3d does. Not sure how easy it would be to do with anything else.

But yeah printing in two parts and joining would be much easier :-)