Sharing Calendar in Outlook via GP or Exchange

[hmdeassis]

Is there a way to share the calendar of an individual(s) in the backend of exchange instead of initiating from within Outlook? So sending a request to share the calendar is not required.

We want to be able to have it automatically shared for all users by all users without having to depend on the user it self to send out a request.

Can this be done via the GP?

Thanks