How can I move both cursors in one graph and zoom out the range between the cursors in a second graph?

Yes exacly this is possible. Click into the graph which should display the zoomed data and click on “Automatic zoom”, the red magnifier button in the Cursor toolbar. Now click into the other graph which should display the whole curve. If you press the CTRL key while you drag one of the cursors, then the range is preserved and zoomed out in the second graph.