I checked the civil registration records for Nordhouse, Alsace and several surrounding towns and did not find anything that came close to what you are looking for (Nordhouse is the French spelling of the name of Nordhausen which is the correct German spelling).
You can look at them yourself for free at: http://etat-civil.bas-rhin.fr/adeloch/index.php
I suggest getting Rosa's obituary. If you're lucky it lists surviving siblings and may have other helpful clues. I also suggest doing the same for her 'sisters'. If nothing else their obits may confirm that they were sisters and possibly point to other siblings. Their death certificates, marriage records and obits may give you the correct town they were from or at least the correct surname spelling.