I'm not really following your specific example, but a worked through example of the "index full breadcrumb" type approach darren was suggesting for doing drill down i na hierarchy is described in slides 32-35 of this presentation (which was recorded as a webcast)...
http://people.apache.org/%7Ehossman/apachecon2010/facets/ http://www.lucidimagination.com/why-lucid/webinars/mastering-power-faceted-search in general, i *strongly* recommend that you use unique ids for each "node" of your taxonomy as a way to avoid confusion when multiple nodes have the same label/name. (in the presentation i talk about doing that, but the slides show simple strings to help viewers follow what's going on) -Hoss
