My Solution is not at all to use "multiple expression maps" and not at all "multiple expression maps for the same instrument".
You can use Expressionmap part in the Control-line on the upper side of the Cubasescreen a bit like a "dropdown menu" but still it is not reasonable to list there all articulations VSL offers. This is in any case simply much to much!
Thats why I left the expression maps only decide a class of articulations and chose the different possible variants of a staccato or legato via controlling the VI-Matrices from Midi-CC's this way you simply multiply the amount of reachable articulations without having endless expresssion-map-lists no one can reasonably handle in any way.
The "mistake" of Steinberg was that they believed the amount of different articulation which appears in the notation of a piece would be the same as the amount the Instrumentalist knows. They simply didn't thought about what VSL demonstrates very well that there are a lot of muscally reasonable different way to play the same notated articulation.
But ...aslong as the VSL-Superpackage-Users dont have the majority in the World of Cubase-Users I dont se any other solution than to blow up the expression map via CC controlled Variants inside VI.