Applications :: Unable To Make Playlists In Itunes / Cannot Sort Music By Year Name

I've only recently added release years to all my albums and now I sort by album by year, which is great. However, I'd like to make some smart playlists based on decades, and this is a problem for anything on some sort of anthology or greatest hits collection. For example, the Barenaked Ladies greatest hits CD was released in 2001.

If I tag the whole album as 2001, it sorts correctly, but the individual tracks from the 90's won't show up in the 90's smart playlist. The other option I can think of is to tag each individual track with the correct year, but then the album stops appearing in the right place chronologically within the BNL albums, since iTunes no longer knows it was released in 2001.

So my question is this: is there some way to do a sort of "Sort Year" or "Album Year" similar to "Sort Artist" or "Album Year"?

And while I'm at it, I'm sure there's no way, but it seems like it'd be cool to somehow tie a track to two different albums. Previously, if I had a greatest hits and some original albums, I would erase any duplicates from the greatest hits and only keep them on the original album. However, since the release of iTunes 8 I use a more album-based approach to my music. I use grid view with shuffle off by default, and often just click "Play Album". But if I do that for a greatest hits comp, it of course won't play the tracks that I've deleted from it. So I have to keep two copies of the same recording for two different albums. It'd be cool if there was some way to tie one track to both albums to avoid dupes. But again, I'm pretty sure this'll never happen.