You can simply buy some gluten and add it to your regular, all purpose king arthur flour to make your own bread flour. There should be a ratio on the box of gluten to help you figure out how much to add. You can find vital gluten at Whole Foods and most health-food stores. Good luck!
Makes complete sense, thanks. If anyone is interested here's the ratio: 1 cup of all-purpose white flour + 1 tsp of vital wheat gluten OR the amount of vital wheat gluten to be added is 2% of the flour weight