In a large mixer bowl, combine 2 cups flour, yeast, sugar, cinnamon, allspice and salt; mix well. In saucepan over low heat, heat 2 cups milk and butter until very warm (120 - 130 °F; butter does not need to melt). Add to flour mixture. Blend at low speed until moistened; beat 2 minutes at medium speed. Beat in orange peel, 3 eggs and 1-1/2 cups flour; beat 2 more minutes. By hand, stir in raisins; then add 2 cups flour. Knead on floured surface until smooth and elastic, about 10 minutes, working in 1/2 cup more flour. Shape dough into a big ball; place in greased bowl, turning to grease top. Cover; let rise in warm place (80 to 85 °F) away from draft, until double in size, about 1 hour.
Punch down dough; turn onto floured surface. Divide into 24 pieces; cover; let rest 15 minutes. Grease 13 x 9-inch pan. Shape dough into balls; place in baking pan. Cover; let rest in warm place until balls double in size, about 45 minutes. Preheat oven to 375 °F. Beat remaining egg. Cut a cross in each bun; brush with egg. Bake 20 to 25 minutes until golden brown. Cool in pan on rack. In bowl, mix confectioners' sugar with 1 tablespoon milk. Spoon icing into decorating bag fitted with writing tube; pipe cross on each bun.