1998 Chevy Tracker Seat Belt Installation

Hi,
I am considering buying a Chevy Tracker.

There are only 2 seat belts in the back seat.
Can I install a third seat belt to the back seat?
There is a metal curved bar in the center right at the back of the back seat - it looks like a seat belt could be hooked to this and put through the upholstery.
Is there any manufacturer directives regarding this because I want to be able to put three children in the back seat safely?

If I can't put that 3rd seat belt in the second seat then I can't buy the car.

Thank you!