Need table references for Managed Object Groups / Element Set

I have created an Object Group of the type Element Group and added a few elements to it.

Now, I am trying to retrieve the list of elements from a BIP (BI Publisher) Report. I’m referring to the PAY_OBJECT_GROUP_AMENDS table, where I see a column named OBJECT_ID.

I would like to understand the primary key reference or mapping for OBJECT_ID, as I’m currently unable to join it with the Elements table.

Any guidance or help on how to correctly join these tables or sql to retrieve the element details would be greatly appreciated.