GrandParent External ID

Summary:

Hello Community,

I had applied the functionality where we fetch Resource Ext ID, Parent Resource Ext ID on activity details page via "Set Property". This is working as expected.

Now, I want to increase my resource family details and need Grand Parent Ext ID on the activity details page.

I have referred the document , But there is no information of getting grand parent of the resource.

Do we have any placeholder that gives me this result ? I have attached the reference of the set up done for resource and its parent.

Please assist any document or steps with which I can get the detail of the grand parent.