Yes, in the example there are 3 tables virtually joined together. But the problem is that they use 2 columns for linked reference. See the blue keys in the picture below.
![Kelly_0-1587929262490.png Kelly_0-1587929262490.png](https://community.jmp.com/t5/image/serverpage/image-id/23484i43058959E0270F67/image-size/medium?v=v2&px=400)
I would like to use only one column to link reference multiple tables.
I know it is possible to virtually join N tables if I use N -1 columns. But I would prefer not to have N - 1 duplicate columns.