In a large bowl, pour the boiling water over the biscuits Stir in salt, shortening and molasses. Cool to lukewarm.
In a small bowl, dissolve yeast in warm water. Add this to the lukewarm biscuit mixture. Stir in the flour, 1 cup at a time, beating well after each addition. When the dough has pulled together, turn it out onto a lightly floured surface and knead until smooth and supple, about 8 minutes. Lightly oil a large bowl, place the dough in the bowl and turn to coat with oil. Cover with a damp cloth and let rise in a warm place until doubled in volume, about 2 hours.
Deflate the dough and turn it out onto a lightly floured surface. Divide the dough into three equal pieces and form into loaves. Place the loaves into two lightly greased 9x5 inch loaf pans. Brush tops of loaves with 1 tablespoon vegetable oil. Cover the loaves with a damp cloth and let rise until doubled in volume, about 1 hour. Meanwhile, preheat oven to 400 degrees F (200 degrees C).
Bake in preheated oven for 45 minutes, until bottom of loaves sound hollow when tapped.