I have tried below setup,

GridContainer (1 column)
  -> PanelContainer (stylebox bg color 1)
       -> HBoxContainer
            -> Label1 (size flag expand horizontal)
            -> Label2 (size flag expand horizontal)
  -> PanelContainer (stylebox bg color 2)
       -> HBoxContainer
            -> Label1 (size flag expand horizontal)
            -> Label2 (size flag expand horizontal)

Programmatically inserting as many PanelContainer and it's child labels as I need...

Everything fine except the column will not resize according to it's content.
Is there a better way to do this?