In a mixing bowl, dissolve yeast in warm water. Add the bananas, sugar, milk, butter, salt, eggs and 3 cups flour. Beat on medium speed for 2 minutes. Stir in nuts. Stir in enough remaining flour to form a stiff batter. Do not knead. Spoon into two greased 9-in. x 5-in. x 3-in. loaf pans. Cover and let rise in a warm place until doubled, about 1-1/2 hours. Bake at 375 degrees F for 25-30 minutes or until a toothpick comes out clean. Remove from pans to wire racks to cool.