Complex sentence: Canada, Japan and the United States are not participating in the tournament for 2016 and 2017 due the 2019 Rugby World Cup qualifying format-the top two teams on aggregate across the two years qualify for Japan 2019.
Split into simpler sentences: Canada, Japan and the United States are not participating in the tournament for 2016 and 2017 due the 2019 Rugby World Cup qualifying format. The top two teams on aggregate across the two years qualify for Japan 2019.