Product Linked Item Search Spec

Hi

The current product structure we have is :-

Root Bundle -> Child Product -> Grand Child Product

Now we have a field at Quote Line item level which is getting populated at Child Product Level. But we need to use that value at Grand Child Level for CSR validation rule. We have used a linked item at Grand Child Level to fetch the value but it's not being fetched.

Can you please suggest how to fetch the value using linked item if we customize the product at Root Level.