Various, Various Artists, Various artist
add a rule to force the same name for "Various_Artists" as album artist, if track artists are not equal.
Christian L. commented
the value "Various_Artists" should be changeable in rule settings.
Reason: May in Germany they want German Text here
I guess this is the other side of http://ideas.blisshq.com/forums/21939-bliss/suggestions/2739754-automatically-complete-album-artist
i.e. if there's no consistent artist, use "Various" (or whatever you want!)