 By contrast, during the same period the German Wehrmacht Army Groups, particularly on the Eastern Front, such as Army Group Centre significantly exceeded the above numbers, and were more cognate with the Soviet Strategic Directions.Naval organization at the flotilla level and higher is less commonly abided by, as ships operate in smaller or larger groups in various situations that may change at a moment's notice.However, there is some common terminology used throughout navies to communicate the general concept of how many vessels might be in a unit.