Alas, there is no easy way to do what you describe. Your options are either to create and use an independent bibliography (search your help file for “Independent Bibliography” for more info on that) or, once you’re finished working with your Word document, to delete the field codes (“Remove Field Codes” or “Convert to Plain Text”, depending on your versions of Word and EndNote) and then add the extra bibliographic entries as a final step before printing / submission.
That would work if your bib is sorted alphabetically and your citations are author-date, but if you ever need to change to a numbered style or to a bib sorted in order of appearance, you’d be in trouble.
No, I understood what you meant, Leanne. Your workaround is viable, and easier than mine, but I think it’s less flexible. Same destination, different paths.
It’s worth noting that EndNote for Pages on the Mac has a handy check box for “In Bibliography Only” that solves this issue – it does exactly what the name implies, inserting a cite only in the bib and not into the text. The cursor position determines where in the bib the cite appears, if it’s sorted in order of appearance.