These seem to need manual follow-up: https://tools.wmflabs.org/mix-n-match/#/search/Geschwister?include=2040
Ideally, they link to an item for each sibling with "has part".
I came across two of them on Wikidata:Database_reports/identical_birth_and_death_dates/1. Sample: Q59601849 (where we already have Q2755963)
Also, if there is no property for it, maybe "described at url" could be added.