Out of the box, rhythmbox does not have the ability to differentiate between different "greatest hits" albums because it treats album titles as the unique identifier.
Through the rhythmbox plugin coverart-browser, we treat both the album-title AND the album-artist as the unique identifier.
As the picture shows - two artists with the same "greatest hits" titles but the albums are shown separately since the two albums are by different artists.
You should note - when ripping CD's, often the album-artist is not ripped and is left blank.
Worse still, for multi-artist albums (compilations), both the album-artist and artist fields are also left empty. Thus you can be left with two albums with exactly the same title.
The trick here is to select all the tracks for an album, right-click and choose properties and then fill in the album-artist field to make it unique
See the links below for installation instructions.