In iTunes 9, you can now do this. First add rule A and set the top “Match” criteria to All. After you have rule A done, click on the three-dot button to get a lower level rule, add rule B and set its applicability pop-up to Any. Finally, click the plus sign and add rule C. This will create the logical structure of A and (B or C). You can get even more fancy and click the three-dot button again, and add a D or E conditional, giving you a final rule structure of A and (B or C and (D or E)).

Smart Playlists in iTunes 9 is a post from: My MacOS X