When I first started using Photo Mechanic, it was possible to set the delimiter character. In update or upgrade (maybe it was version 3 to version 4 I don't remember) that option disappeared and PM went to the pipe. Kirk and I exchanged a couple of emails and I got the same response: it's the way Adobe does it. Anyway, I didn't use Adobe products and needed a colon separator for my catalog program. I hope I'm remembering this correctly. I think this was my workaround, Actually, a couple thing to try.
In the Root column set your first level. In the child column set both the root word and the child word separated by the delimiter you need. In the third column set the root, child, and second child.
It would be something like this using the colon as a separator:
Root Animals
First child Animals:Mammals
Second child Animals:Mammals:Bears
You get the idea. It's not as clean as it would be using the default delimiter but might work for you.
Another workaround would be to use only the root and list every level of the hierarchy.
Animals
Animals:Mammals
Animals:Mammals:Bears
Again, it isn't as clean as the default but might work to get around your problem.
I hope I'm remembering this correctly. My catalog app now allows the user to set the delimiter so I've changed to the pipe as a separator so the PM default works ok.