Heating a deep sauce on medium-high heat, add the butter. Once butter starts to melt, add hot links. Cook for 5 minutes, until sausage looks a little carmelized. Add chopped onions. Stir for 3-4 minutes, until onions are al dente. Add BBQ sauce along with the brown sugar. Let simmer for 2-3 minutes on medium until brown sugar is dissolved. Add all the beans, stir the mixture and let simmer for 15 minutes on medium-low heat. Serve with Hawaiian rolls or your favorite bread.