Thanks for the inputs.
@Vincent Kars: I don't want to rename but keep both folders - the folder with Hi-res on the nas and on the ssd
@eddyshere: two libraries would be fine, but it doesn't really work, because every new library has the same settings like the older one. I could not manage to set one library to the nas and the other (like "lokal") to the ssd. Perhaps I miss something...
But thanks anyway.
Cheers,
Harry