A while back someone wanted to make a virtual/pseudo compilation album using their Beatles albums. This is what
I did to create their Red and Blue compilations.
Select The Beatles using iTunes browser
Select tracks and add to Comment field :
The Beatles 1962-1966 (Red Album)
Sort using Comment column
Add compilation track order into BPM
BPM = 101 for "Love Me Do",
BPM = 102 for "Please Please Me" etc.
For the Blue Album I numbered
BPM = 201 for "Strawberry Fields Forever",
BPM = 202 for "Penny Lane" etc.
So when I'm browsing The Beatles and want to list the Red and Blue albums I sort the BPM column.
I also found this method useful with the
Police collection Message In A Box,
BPM 101 - 110 for Outlandos D'Amour,
BPM 201 - 211 for Regatta De Blanc,
BPM 301 - 311 for Zenyatta Mondatta,
BPM 401 - 411 for Ghost In The Machine,
BPM 501 - 511 for Synchronicity,
BPM 601 - 624 for the live/alternate tracks included in the box set.