Combine orange juice and gelatin in a small saucepan; stir well. Add milk and sugar, stirring well. Cook over low heat, stirring constantly with a wire whisk, 5 minutes or until sugar and gelatin dissolve. Cool slightly.
Beat cream cheese in a large mixing bowl until light and fluffy. Gradually add gelatin mixture, beating constantly. Fold in orange sections. Chill until mixture begins to thicken.
Beat whipping cream until soft peaks form. Fold into orange mixture. Spoon mixture evenly into tart shells. Chill until set.
Note: Two (11-ounce) cans mandarin orange sections, well drained, may be substituted for fresh orange sections.