If you're dealing with compilation albums, make sure to use something like "Various Artists" as the <album artist>. If you don't, each artist's tracks will seem like a different album. If <album artist> is left blank, then MB treats it as if it is <artist>.
Also you can/should enable the "itunes compilation" flag in the Tag Editor > Settings. Select the entire album first, then Tag Editor > Settings
If that doesn't do it, please post a screenshot of what you're seeing.
Also, this has been discussed and answered many times before, so it would be helpful to those of us who have answered this previously if you do a more in-depth search before posting.