No, this cannot be done with the existing CSS, you will need to add the table manually.
Use Split view mode, and select the Form Element that would like to add the checkboxes after, in the Tag Selector, select the Line Group Div.
copy that div, and paste a new one after it to create a new line group to add the checkbox table to. you'll want to remove all the other code from the div, so it is just an empty div with the class set to lineGroup. See the attached screen shots