References that are listed in the bibliography should only reflect those that were cited in-text. Adding non-cited references to the bibliography misleads the reader about the references and superficially extends the list. It seems contradictory to say that the non-cited references “informed the paper” and yet not cite them in-text or at least acknowledge them in a footnote. If you wish to pursue adding non-cited references to the bibliography (incorrect as it may be), you can edit the citation to “Show only in Bibliography”.
Although I disagree with your construction of the bibliography, to answer your question, instead of manually cross-referencing the bibliography with the group, couldn’t you just split the references into two groups – “Cited” and “Non- Cited”? Then while working you know exactly which references belong each group.