Select pairs, which exist in any branch of the two tree lists.

Hi

Could anyone please help me to select pairs of items, which occur in any of the branches in these two lists?

For example from the lists on the attached picture I need to get:

      :{0}

6

14

      :{1}

1

9

      :{2}

2

10

      :{3}

3

15

      :{4}

5

11