Need to indent items in controls that don't support it, like the Checkbox group or Radio Button Group?
- Duplicate your control
 - Remove lines that need to be indented from the first one
 - Remove all lines except indented ones from the second one
 - Overlay second control on the first one
 - Select both controls (easest to do with CTRL \ ⌘ + A)
 - Group the controls together from the menu (or press CTRL \ ⌘ + G)
 

You can even transform the group to a symbol. This will make it easier to use from the UI library or search.