How to Install Back to Back Wall Hung Toilets on 1962 Rough-in Stack

[Lacy]

How do you install two 1960’s style wall-hung residential toilets back- to-back on an existing 1962 cast iron pipe? The original pipe is fully accessible and has back-to-back 3-bolt brackets for the toilets, but the wall and carrier(s) are not installed (yet). The plumber says it is impossible to install wall-hung toilets back-to-back, even though another pair was installed on the upper floor of the house in 1962. Is it possible to also attach a washing machine drain and a shower drain to the existing cast iron toilet pipe at the floor level? The goal is to avoid cutting concrete.


Thank you.