bathroom stack is in the wrong place!

Ok we didn't have a choice, we demo'd the master shower. Now that we are putting it all back together, as a tub/shower we noticed a huge problem & I would love to hear any advice ya'll might have. The air stack between the 2 bathrooms has a joint that sticks out about an inch beyond the studs. The previous solution to this was 2 layers of sheetrock. Now we do plan to tile the surround, but would not like to have the alcove to be different dimmension than the rest of the room (it's a tiny room). So what do we do? The stack is cast iron & isn't gonna budge. My guess is to shim out the whole wall to fit around that joint. Any other ideas?

pipe

If two layers of sheetrock covered it previously, then two layers on the entire wall, it is a small room you said, should also fix the problem.

Thanks, I talked to my plumbers & they said they could replace the cast iron with a pvc pipe for little cost and then we won't have to try to work around that one joint. I'm all for that!