Complex sentence: This put them in a position of power but the only viable purchaser was the sawmill, which meant that the sawmill was able to exploit its position over the farmers as it was the sawmill defining the price.
Split into simpler sentences: This put them in a position of power but the only viable purchaser was the sawmill. This meant that the sawmill was able to exploit its position over the farmers as it was the sawmill who defined the price.