Grupo de Ejércitos B
In 1942, Army Group South was to spearhead the German summer offensive in Russia known as Case Blue. The 17th Army was to give flank protection to 1st Panzer Army as it struck towards the Don River. From June to July, the German 17th Army, the Italian Expeditionary Corps in Russia, and the Romanian 3rd Army were organized as "Army Group Ruoff". In August 1942, Hitler sub-divided Army Group South into two new army groups: Army Group A and Army Group B. Army Group A included the 17th Army, the 1st Panzer Army, and the 4th Panzer Army. Army Group B included the 2nd Army, the 6th Army, the Italian 8th Army, and the Hungarian 2nd Army. By October 1942, the Romanian 3rd Army and the Romanian 4th Army were added to further bolster Army Group B.