CUI third accordions - Can we display items from next relationship level?

Hi community,

I am playing around with "3rd accordions" which can be configured with CUI in the newer Aras version (12SP9+).

So far I was able to display regular item data like related "Documents" in my 3rd accordion. Just as described in this blog: 
(3rd accordion are mentioned in the last section that also indicates Aras Labs hidden and desparate love for accordion music).

I wonder if we can also display multi-level content in the 3rd accordion?

So not just data from the item we have already opened, but from the item two levels below? 

Example of the structure I want to achieve:

Main Form --> Single Part (level 1)
BOM Relationship --> Related Parts (level 2)
3rd accordion               ---> Related Documents from level 2 (!)


Main Form --> Single Part (level 1)
BOM Relationship --> Related Parts (level 2)
3rd accordion               ---> Related Parts (level 3)

I assume we can pass some further "additional-data" attributes to influence the shown level, but I haven´t seen any example yet.
For displaying multi-level data a tree-grid-view is of course the better option. But I wonder if we can also use the CUI accordions for these kind of data.

Does anyone know more?

Thanks and best regards!