Preheat the oven to 350 degrees F (175 degrees C). Grease and line with buttered wax paper two 8 inch round pans.
Cream together margarine and 1 1/4 cup white sugar until light and fluffy. Beat in eggs and orange rind until thoroughly combined. Stir in 1/2 cup orange juice and milk. Combine flour, baking powder, salt, and baking soda; stir into creamed mixture, and beat with an electric mixer at medium speed for 2 minutes. Blend in orange food coloring. Pour batter into prepared pans.
Bake for 25 minutes. Cool 10 minutes, and then remove layers from pans. Peel off wax paper, and cool completely on wire racks. Split each layer of cake, making 4 thin layers. Sprinkle layers with 1/4 cup orange juice.
Sprinkle gelatin on the cold water in a small cup; let stand 5 minutes. Place cup in boiling water bath, and stir until gelatin is dissolved. Remove from heat, and set aside for a minute. Whip cream with confectioners' sugar until just starting to thicken. Continue beating while you add the orange juice. Slowly pour in gelatin, and combine thoroughly. Beat until stiff. Fill layers with orange flavored whipped cream.
In a double boiler, combine squares of chocolate and butter or margarine; stir until melted. Let cool until chocolate thickens somewhat. Pour chocolate on top of cake, letting it drizzle down the sides. Refrigerate cake for 24 hours. Let cake sit at room temperature at least 1 hour before serving.