The Curse of Musician's Versatility

There are a lot of programs in the marketplace that allow PC users to catalog, tag, and organize their MP3 (or other media) collections. Programs such as Musicmatch, iTunes, Real, and Windows Media Player.

My common gripe across all programs in their lack of multi-genre tagging. Let me take a moment to explain what I mean. Take the heavy metal band, Metallica. They have a couple of instrumental songs ... like Orion (from Master of Puppets). My genre tags include Heavy Metal (which currently lists Orion) and Instrumental Rock. What do I tag Orion as? Instrumental Rock, since James Hetfeild doesn't sing? Or Heavy Metal, since Metallica firmly belongs in that genre? The same goes with artists like Joe Satriani (who sings on a few tracks, notably in his Flying In A Blue Dream album) - do I tag Ride as an Instrumental Rock song or a Hard Rock song?

What I would like to do is to tag them as belonging to both genres. I don't think this is possible under any current (mainstream?) software. I hope someone implements this soon.