Showing path / directory tree (or taxonomy) in Kibana

Hi,
I have an index containing information about files. One of the fields is the path of the file. Now, I need to show a directory tree and show how many files are there in the directory and all sub-directories, and potentially perform some other visualizations on the selected sub-directory.

This is actually a little more generic problem, because it is similar to the taxonomy tree problem. I thought about following the idea presented by Doug Turnbull in the Relevant Search book, but he uses analysers in full text search, which is not an option for the aggregations in Kibana.

I am guessing that this is more a kind of data structuring, but I can't come up with a proper solution other than duplicating the documents for all parent directories, which is not a very efficient solution.