Expression maps - group use

I remember reading that you’re using the group function to program, among the other things, violin and violin divisi using the group function within Expression Maps, so you can jump between violin and violin divisi switching group while keeping the same set of articulation.
I use a lot Expression Maps, I read the manual and it’s not very clear to me how to program/use the group function.

Could you talk a bit how you set it up on your system?
I don’t use VSL at the moment, but I could use this concept with other libraries.

Of course, any idea from anybody is very welcome !