hear hear

I bet the multiple parentage requirement is editorially-driven? I'd go for a symlinking mechanism rather than genuine multiple parentage, if you really want to keep a close match between visible and underlying structures. If not, create a layer of abstraction between the two, as perrin suggests.

One of my old employers is still, five years later, suffering from my conviction that there was a logical structure into which everything would fit and that once we'd built it, all we would need to do is show it to people. It turns out that editorial content isn't really like that :(