When I lived in Portland I went to replace the duel mufflers on my 80 Bronco and the shops in the Portland area would not modifie the exhaust on the truck, even though they were already duels on it and my adress was still Central Oregon. So check with the shop that is doing the work.
You are asking if can have your exhaust modified so that it dumps out before the rear tire?
I'm no expert of diesels or exhaust systems... My suspicion is that it could be done. It will depend also on where you live, do you have a DPF or catalytic converter. Do you have to pass an emissions test?
On my 7.3 Powerstroke I know it's possible. However, when you get into the skinny pedal and smoke is roaring out of the exhaust I wouldn't want that crap all over the side of my truck... maybe in the rice grinder next to me though.
You might want to post your question on the diesel forum appropriate for the engine on your truck.