Without seeing the assets, it would be hard to say what would be best. So let's look at some assets from a tile-based game.
Do you see those boxes in the picture? They are composed of multiple parts (tiles).
A 9-patch will allow you to create boxes like the ones from the screenshot using a single image.
If you put the above image into a 9-patch, set all of the margins to 16, and set the edges to tile, you will have a single object that you can resize at will, and all of the 'parts' will automatically be rendered in the correct places.
If your assets are not tile-based, then you will need a different approach. In the interests of keeping memory usage down, you may want to add each graphic as a separate sprite, and use containers and/or event logic to keep the parts together. You may also want an invisible object to handle the game logic of the platform (such as collision and movement), and just have the art assets move along with it.
But, as stated at the beginning of this post, it's hard to say what you need without seeing the assets (or at least a better description on how they fit together). Everything in this post is speculation as to what you might need.