Sometimes it is useful to have links inside of alphabetical index, e.g. "[index item], see [index item]". So far it seems to be not possible in Libreoffice.
This is a feature/enhancement request, therefore changed 'Importance' field to 'enhancement'.
Summary amended for clarity. This appears to be a request to include an equivalent of these types of elements:
... which are available in OASIS Darwin Information Typing Architecture (DITA) but not OASIS OpenDocument Format (ODF). There are clear examples of how this would work under the link for each element here:
There does not appear to be any OASIS issue in JITA related to enhancing ODF in this manner.