WARNING: UGLY HACK AHEAD!
Have your air sickness bags at the ready...
I decided to create a fake plain text attribute in the SystemSettings BO called FauxSeparator with a character count of 1 and an initial value of |. It didn't work because you can't reference SystemSettings in either a calculated column or a shortcut.
So I created a fake plain text attribute in Account (uppermost parent BO) called WTF_Separator with the same settings as above and created a shortcut to it. That worked. You would need to create a different shortcut for each separator at each level of the tree.