What Limnos said originally should work
Quick answer: Select all the tracks on the album, then go to File > get info, and either give them all a single "album artist" or check the "compilation" flag.
But also, if there are blank spaces after the - album artist name - in the get info window, that can throw iTunes sorting off too, if different tracks have any variation at all in album artist name among the songs, then they probably won't sort together. Also the same applies to the album title field, even differences in extra blank spaces can make iTunes think there are different albums (I have had this happen). Also in get Info you might want to look at the - sorting - fields, sometimes variations in those can cause songs to not appear as a single album. What you are describing sounds like a metadata problem that you should be able to correct with Get Info tags.
Hope this helps, good luck.