You will need to find a good shipping company (I would recomend Interlink express, but I don't know who they use in dear old Deutschland)who will ship either by weight or volume. I would suggest volume is a smart move, as wine is fairly dense stuff.
So, you purchase the familly vino paying all taxes in Germany, and the shipping agent collects it. (if you do use interlink, then make this on the last day of your holiday). you then return home, and receive your 'parcels' which will have a US duty request on them. Yo pay the US duty, and collect your wine.
Now, you've paid for shipping, and two lots of tax - a very expensive case or two of wine - but you can claim back the tax paid in Germany, to sweeten the pill somewhat - you need to collect a form from German customs to be able to do so.
Have fun!
Owen
