Merging Layers

Hey, im trying to move from animate to harmony but im having trouble with the way i animate some things. In animate sometime i would draw and object lets just say a cube to be simple and i would draw each side of the cube on a different layer (Just one line). The i would shape tween (Morph) each line to its now position creating the new image. I would then keyframe each frame and merge the layers. This game me the animation with an object that i was then able to colour fill. How would i go about doing this in Harmony as when i try and merge layers that have been morphed it morphs it as one object but the objects im trying to morph are to complicated for that which is the reason i morph one line at a time

Thanks