DataGrid Parent - Child - GrandChild Question

The example works great, I''m using it for my bridging table (one to many) from Customers to Addresses. The thing is, I want to list ALL Addresses, not just the ones you select in the ParentChild grid. Thus, I want, if you click on the Parent record, to directly display ALL grandchildren for that specific record and not display the 2nd grid at all. Any help would be much appreciated!!

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