In a large bowl combine 3 cups hot water, the sugar, salt, oil or butter and the dry milk powder. Stir well and allow to cool to lukewarm. In a small bowl combine 1/2 cup warm water (100 to 115 degrees) and the yeast. Let stand for 5 minutes to dissolve. Add the dissolved yeast and 2 cups of the whole wheat flour to the first mixture. Stir well. Cover and let stand 10 minutes (or longer if you wish). Add remaining whole wheat flour. Then add 2 cups bread flour, oat flakes, bran, cornmeal, bulgur and semolina, if used. Mix well. Turn out onto a floured board and knead for a minute or two. Then cover with a bowl and let rest 10 minutes, adding just enough of the remaining flour so that the dough is not sticky. Resume kneading until the dough is elastic, 8 to 10 minutes. Place dough in a large greased bowl. Cover and let rise in a warm place until doubled in bulk. Punch dough down and shape in 3 loaves. Place in 3 greased loaf pans. Cover and let rise until just double again. (Do not let dough get too light or it may fall when transferred to the oven). Bake at 375 degrees 40 to 45 minutes. Remove from pans and cool on racks.