There are a couple of ways that I think might do what you're looking for, functionally.
You can select your objects and group them; menu Modify > Group or keystroke Ctrl-G. This gives you one object you can work with in the layers panel, to move or copy, but you can always ungroup one of your copied objects to modify it later.
You can select your objects and flatten them into a bitmap object; menu Modify > Flatten Selection or keystroke Ctrl-Alt-Shift-Z (oh yeah, that's memorable :P). This gives you a bitmap that you can't edit as a vector in the future.
You can also use symbols. Select the object/s and press F8 to open the symbols panel.
You can reuse symbols, edit, resize etc..
You can select modify> flatten selection. Make sure you save a different version of the image with all it's layers before you flatten them or you may lose them.
Then you can export the image as a .gif or .jpeg.