You can access grandchild data from a parent level in Conga Grid. For example, you can create a grid of Accounts that has a child grid of Contacts and a grandchild grid of the Contact’s cases.

To create a grid of Accounts that has a child grid of Contacts and a grandchild grid of the Contact’s cases:

1. Go to the Conga Grid Setup tab. Select Accounts > Tabs & Related Lists. In the Tab Creation section, click Single Conga Grid.
2. Follow the instruction to create a Single Conga Grid tab.
3. Return to Conga Grid Setup tab and select Account again. Click Single Conga Grid in the Page Layout section.
4. From the Select Relationship drop-down, select Contact (AccountId). If you already have a view saved for a Related List view of Contacts, select it from the dropdown. Modify the label and click OK.
5. Go to your Conga Grid tab of Accounts. Click Reading Pane > Configure to open the Configure Menu. Click Reading Pane > Visualforce Pages.
6. From the options in the Visualforce Page, check the box next to your grid of Contacts. It appears as a tab in your Reading Pane. Close the Configure Menu in the Accounts grid.
7. In the Contacts grid, click Reading Pane > Bottom.
8. When the Reading Pane in the Contacts grid opens, click the ‘+’ icon to find the Related List selections for Contacts. Check the box next to Cases.

Now when you have a Record selected in the Account Conga Grid, you can see the Contacts related to the Account, and the selected Contact’s Cases.