New a graph
Open Y axis dialog and go to ref lines tab. Set ref lines at axis value 1.5, 2.5 and fill to each other.
Go to Breaks tab. Select Horizontal in left panel. Set Number of breaks to 1 and click OK.
Click the left part. ? Ref lines can be selected. Double click will open axis dialog’s ref lines tab.
Click the right part. ==> Ref lines could not be selected. Double click will open PD dialog