1. Item 1
2. Item 2
   1. Item 3
   2. Item 4
   3. Item 5
      1. Item 6
      2. Item 7
      3. Item 8
   4. Item 9
   5. Item 10
3. Item 11
4. Item 12

1. Item 13
2. Item 14
3. Item 15
   1. Item 16
   2. Item 17
   3. Item 18

Serialised Output (per list)

Draggable Handles

If you're clever with your CSS and markup this can be achieved without any JavaScript changes.

1. Drag
   Item 13
2. Drag
   Item 14
3. Drag
   Item 15
   1. Drag
      Item 16
   2. Drag
      Item 17
   3. Drag
      Item 18