Ya I see where you are. Guess you gotta do what you gotta do. Can you put them in a cool water bath? Maybe at least just drape a towel over the bottles in a shady but well ventilated area and keep the towels moist so you get some evaporative cooling? Or maybe 89F is perfectly fine and won't harm them at all; I'm just guessing it might not be that great.
I actually loved this beer called Regab in Gabon, central Africa, also on the equator. Could never get it cold but it was perfectly fine with me at 80 to 90F drinking temp. It was a BMC type lager but actually tasty at a higher temp.