Complex sentence: It was formed as the result of an agreement between Holden (the Australian subsidiary of General Motors and Toyota), replacing the earlier Holden-Nissan joint venture that had existed in 1983.
Split into simpler sentences: It was formed as the result of an agreement between the Australian subsidiary of General Motors, Holden and Toyota. For Holden, it replaced the earlier Holden-Nissan joint venture that had existed in 1983.