Consolidate Duplicating Outlook Calendars

Each member of my team now shows up with as many as five separate Outlook calendars and the result is a mess of duplicate events. The core problem is syncing—events continually copy themselves across the extra calendars rather than updating just once... (Budget: £20 - £250 GBP, Jobs: Email Handling, Excel, IT Project Management, Microsoft, Microsoft Access, Microsoft Exchange, Microsoft Outlook, Technical Support)