[Highland Park] plumbing recommendations needed for stack repair

We are looking for a recommendations for a plumber who has experience with repairs on soil stacks in older houses. We have a brick Victorian that apparently has a problem in the stack between the second and third floors. Our usual plumber was able to help us diagnose it but doesn't do those types of jobs. Also, if anyone has gone through this sort of repair before, we'd be grateful for any advice on what to look for in getting estimates. Thanks! - Deirdre