Is there a way to select a group of tiles--as opposed to pixels--to copy, paste, or move?

Is there a way to select a group of tiles--as opposed to pixels--to copy, paste, or move? I'm making some pretty large maps lately and when I realize well into a map that a central room needs to be enlarged, that seems to mean re-placing each tile by hand to make space. Am I missing something obvious or is this a feature that I should request, because being able to drag a room from one part of a map to another would be a major help. Thanks.