I know. That's as far as I got ;-) I know you can use that function, it works with grouped dimensions - but it seems there is no way to give a Name to a Group of expressions.
I guess I remember now why I refrained from using cyclic Groups in the past ;-)
So I'll do it the old-fashioned way and use either two separate Charts or a button to Switch - that way I have something which I can also use to influence other formulas.
For Starters I guess I'll go for separate Charts since I already have some formulas and stuff in the Chart -which would be doubled if I introduce a second Dimension ...
Thanks a lot!