Syncing Issue with iPod Nano 6th Generation-Albums and Songs

I recently received an iPod nano (6th Gen) and decided to manually manage my music, since I have music on both an iMac G5 (OS X 10.5.8) and a MacBook Pro (OS X 10.6.5). iTunes on both computers are up to date. I dragged a number of albums from my iTunes library located on my iMac to the connected iPod nano. All the songs transferred fine. However, once transferred to the iPod, I noticed for some albums, each song appeared as an album, so if I looked on my iPod for a particular album, I'd see it listed there for each song on that album and I couldn't see the songs all listed under that album. I've tried to delete and reload these albums and the same behavior is seen. These albums often contain many different artists. In some cases, I've listed the artist for each track in my iTunes library, in other cases, I've used a generic term like "various artists" for each track. It doesn't seem to matter, since I've seen examples in each case where album grouping is lost upon import to my iPod. I'm not sure this is an iPod issue or a corrupt iTunes music data base. Has anyone experienced this? Is there a solution? Thanks!!