For now there are no possibility to add responsive divider (just line - continuous, intermittent or dotted) that will visually divide different content blocks from each other horizontally or vertically. For now it possible to add horizontal divider with hack - create text field and put as much underscores (or dashes) as you need/want. But potentially such solution could brake alignment and position of other content block in document on exporting to Word (or any other external format) or rendering PDF.