AG Grid - Group specific rows (the ones insider should be collapsed)

Hello guys,

I have an app where the table is fed by a transposed data…

What I’m looking to do is to group two rows (in this case Group Value 1 & Group Value 2) collapsed inside the Sum Total row… If the user clicks, the values will be displayed directly below the Sum Total, possibly indented.

I did search about this on ag-grid documentation, but I didn’t find how to do it as I need.

You can access the MRE here:

Any help is very welcome