Complex sentence: The 24th Infantry Division's regiments, which were already exhausted by two weeks of fighting and seeing consecutive defeats while trying to delay the advance of the North Korean Army, gathered to make a final stand around Taejon, a major transportation hub of South Korea.
Split into simpler sentences: The 24th Infantry Division's regiments, were already exhausted by two weeks of fighting and seeing consecutive defeats while trying to delay the advance of the North Korean Army. The whole of the division gathered to make a final stand around Taejon, a major transportation hub of South Korea.