Multiple Sortable Lists - Outer Join

This example makes multiple sortable lists that are outer joined together. In the example below you will see 2 lists. Both lists are sortable, but List #1 can move its items into List #2 and they become sortable. However, List #2 can not move its items into List #1.

List #1

Item #1.1
Item #1.2
Item #1.3
Item #1.4
Item #1.5
Item #1.6
Item #1.7
Item #1.8
Item #1.9
Item #1.10

List #2

Item #2.1
Item #2.2
Item #2.3
Item #2.4
Item #2.5
Item #2.6
Item #2.7
Item #2.8
Item #2.9
Item #2.10