We have just merged with another company and are looking to share calendars with one another. We are using O365 in Hybrid with Exchange 2013 where as they are solely using O365.
However, we are looking for the ability to assign full access permissions so that we can edit calendars across the two companies. i.e one of their PA's can add an appointment to the calendar of one of their managers.
Is this possible, and if so how? as I can only see information about Free/Busy via federating the servers.