Yes, CiraSync can do this. You will have to perform multiple sync tasks. Each sync task needs to have a different source, but the same targets. Once these tasks have been performed, CiraSync will consolidate all these events into one calendar for all the members of your Office 365 tenant.
Home > Support-Artikel > Kalender-Synchronisierung > Does Calendar Sync consolidate events from multiple calendars into one for all Outlook users?