When the number of possible variants of beginnings of end part of strings is not more than 6 (seventh IFERROR() is reserved for no ending found), then like this:
When there is more possible starts for ending part, then you have to croup IFERROR()'s using IF(). But the formula will be terrible - probably you have to use several helper columns to keep some overview how the calculation is done and which condition is where applied.

Wow!!, This turned out to be much more involved than I first thought. I tried xor’s solution first and it seems to be working pretty good. Reading onto some of the other post I’m seeing more robust, easier to maintain, resource hungry and faster. As soon as I get a chance here I will experiment with some of these other options. Thanks for all the help here.