Are Wagon rear seat belts different?

I only have one belt in the back seat of the wagon. It has a hook that latches to a ring attached to the floor of the wagon. It does not have a bolt at all. How do I add another belt. I have not found any of these clip type belts. Let me know if you have a solution, I would like all 4 of my family to be able to ride in the car with a seat belt.