The war was not just going on in Europe. North Africa was also heavily involved in skirmishes between Allies and the Axis.
As for the connection there was only one country that was fighting on two fronts at the same time: the US. Limiting the WW2 definition to when the US started to enter the War is reductive, I think.
"In effect, Australia fought two wars between 1939 and 1945[2] – one against Germany and Italy as part of the British Commonwealth's war effort and the other against Japan in alliance with the United States and Britain. While most Australian forces were withdrawn from the Mediterranean following the outbreak of war in the Pacific, they continued to take part in large numbers in the air offensive against Germany."
As for the connection there was only one country that was fighting on two fronts at the same time: the US. Limiting the WW2 definition to when the US started to enter the War is reductive, I think.