Solutionunvalidated
Add a flag to the non-grouped rows (or grouped rows) and modify the column `sorter` to return a fixed comparison result (e.g., 0 or higher precedence) for the rows that must stay on top, otherwise use the normal comparator.
7594d6d4-a166-45ea-b94f-89e1dc57df20
Add a flag to the non-grouped rows (or grouped rows) and modify the column sorter to return a fixed comparison result (e.g., 0 or higher precedence) for the rows that must stay on top, otherwise use the normal comparator.