My advice - pack each bottle well: wrap each bottle completely in a large towel and try and carry each such wrapped bottle in a sealed/waterproof bag within the case. Also, make sure no part of any of the bottles is directly in contact with the sides/walls of the case.

Should any or all of the bottles break in transit, the entire contents of your luggage will be ruined. Don't pack anything of value in the same bag as the wine.