There is a British company called multimac that provides an 3 or 4 child multi seat. It is pretty much a bench you can install in your car and it fits in nearly

There is a British company called multimac that provides an 3 or 4 child multi seat. It is pretty much a bench you can install in your car and it fits in nearly all small cars as well. This way one does not need a bigger car when having three kids.