Complex sentence: The front line divisions of the Waffen-SS that had suffered through the Russian winter of 1941--1942 and the Soviet counter-offensive were withdrawn to France to recover and be reformed as Panzergrenadier divisions.
Split into simpler sentences: The front line divisions of the Waffen-SS that had suffered losses through the winter of 1941--1942 and during the Soviet counter-offensive. They were withdrawn to France to recover and be reformed as Panzergrenadier divisions.