First bookmark the original endnote. Then go to the Fields dialog box
and choose links and references in the left pane, and noteref in the
right pane, and see the options you have. The one required option is to
include the bookmark in the field. Choose the "h" option allows you to
jump directly to the original endnote reference.
However, if you want the other endnotes to open the original endnote
itself and not just jump to the original endnote reference, then you
need to bookmark the endnote itself, not its reference number.
Larry