Theoretically yes, practically the area where you change the infill density does not connect to the surrounding area properly in horicontal direction. I have tried this and I failed. At least not if you do it in a straight forward manner. This is due to the fact that every area is surrounded by perimeters. If you set perimeters to 0 it will even connect less because the infill does not "add up" (I don't know if this makes sense) Try it out!
Of course I can be missing something. If you succeed with different infill densities let me know how to do it!
For now I love the idea of Peter because it works exactly as I need it.