Outlook – way to have an Office365 subscribed calendar show as busy for others

Are there any tools that allow you to subscribe to an ICS feed in Office 365, but in reality, SYNCHRONIZE that feed to a secondary O365 calendar?

Use case: I've got my main calendar which I maintain. I'm also subscribed to my 'teaching calendar' which changes occasionally, outside my control. When someone wants to schedule a meeting with me from within my organization, I would like them to know that I am not available during my teaching periods. If events get added, removed, or updated in the subscribed calendar, those changes must be reflected in the 'real' calendar.

I would imagine that there might be a cloud service or sync widget out there somewhere that you could provide your O365 credentials and the ICS URL and it would 'do the magic' — but can't seem to find anything like this.

Thanks!