I have a crack in my soil stack between the first and second floor. I assume the pipe runs vertically, venting through the roof. On the second floor, there are 2 full baths that share a wall. Most of the fixtures are not in proximity to the main pipe, and I have no idea what type of connections they have. Accessibility is terrible, as there is brick wall on 2 sides of the pipe. Pipe is cast iron. I was planning on cutting out about a 5 ft section of pipe, on either side of 2 joints (can't tell if the upper joint is leaking, or the crack goes to the joint), and using a collared no hub connector to PVC on either side. My neighbors had a similar repair done about 6 years ago, done that way. Couldn't find if there were any code/other issues with that. My main concern is what's supporting the cast pipe above where I'm cutting?