Link to grouped Parent

Not sure whether the complexity of this would justify the feature, but would be powerful ...

Say we have parent orders and child orders.
We link childOrders to parentOrders.

Now we group parentOrders by account.

We no longer have any meaningful linking relationship between the aggregated rows (the 'account' level rows) and the child order rows.

Would be great if we could select an account in parentOrders and see in the childOrders below all the child orders associated with parentOrders for that account.