LaTeX's indexing packages
xindy provide good support for the basic features of an index: runs of pages, nested index sub-entries, and cross-references of the form:
Yurmurm-Peffifoss, Rudwooll, see Peffifoss, Rudwooll Y.
Well and good. However, my indexer also demands an additional type of index entry, the "see also". A see-also entry combines page references and cross-references into a single item:
Peffifoss, Rudwooll Y., 58–59, 65; see also "The Preoccupation of Mr. Peffifoss"; Thurber, James, nightmarish bureaucratic fantasies of
Is there a ready-made command for such an entry?