Both the Kameha Grand in Bonn and the Excelsior in Cologne have shower/bath combo rooms in the suites which are almost big enough for a group shower/bath. By this I mean they have a shower and behind that a separate bath all enclosed in the same enclosure. Theoretically someone can be in the bath while the other is in the shower all behind the same glass door. The only annoying thing is that you can't turn on the rain shower and the hand shower at the same time.