Complex sentence: The school district and its insurance company, Graphic Arts Mutual Insurance Company, filed federal lawsuits against each other in April 2010 over who should pay any settlements by the district, and the related bills.
Split into simpler sentences: The school district and its insurance company, Graphic Arts Mutual Insurance Company, filed federal lawsuits against each other in April 2010. They argued over who should pay any settlements by the district, and the district's related bills.