Scald milk; add sugar, salt and shortening. Cool to lukewarm. Sprinkle yeast on warm water; stir to dissolve. Combine milk mixture, 1 cup whole wheat flour and 1 cup unbleached bread flour. Beat well with electric mixer for 2 minutes at medium speed or 8 minutes by hand. Scrape bowl occasionally. Add yeast mixture and eggs and beat well. Stir in whole wheat flour and enough unbleached bread flour so dough leaves sides of bowl. Place in greased bowl, turn over to grease top. Store covered in refrigerator. Remove 2 hours before shaping. Turn onto floured board, knead, shape as desired. Place on greased pans. Cover, let rise 1 to 1½ hours in warm place. Bake at 400 degrees for 15 to 20 minutes or until done.