Ability to expand to bottom level descendants in Forms

Summary:

We are running into a use case where a client would like a form to be at a "Total" parent level and then once expanded to show bottom level members. ILvl0Descendants would not work since it would not include the parent. I Descendants will not work since the customer does not want see all the generations, just the top and bottom.

Looking for a functionality similar to "Zoom to Bottom" in reports

Any ideas to make this happen in Forms would be appreciated!

Content (please ensure you mask any confidential information):

Example: "Total Business Partner" to show then once expanded "All Business Partner" and "Total Vendor" to not be seen.