You can have multiple docks attached to a given side, but you can only have one open at a time. You would open/close/toggle docks on a given side using the Dock ID. You can also use this to “override” a shared Docked View.
From your screenshot, if you did not want “Header” displayed for a given Page Configuration you would create a second Docked View with the same path, and then specify for the second (local) configuration of the docked view to be onDemand and hide its handle.
I think there’s an “idea” post about having multiple docks at a given time, but implementing that could be a bit of a nightmare because we’d have to track the order they were opened, or maintain a registry which would dictate in which position a docked view would open with regard to the others.