Load Rating index of 99 can handle 1,709 pounds x 4 = 6,836 pounds / 2.2 = 3,107 kgs.
Listed weight of the GS (according to
Hyundai Grand Starex | Auto Search Philippines) is 2,204 kgs curb or 2,770 kgs gross. That's about 337 kgs of leeway. Should be ok. How often is it fully laden?
For reference, I've been on tires with load index of 97 (1,609 x 4 = 6,436 / 2.2 = 2,925 kgs). Mas mabili nga lang naupod yung goma, though not sure how much of that is because of the weight and how much is because of the tire's inherent treadwear. Just make sure to abide by the tire pressures indicated on your driver's side door.