Since this is a secondary calendar folder -
The owner of that folder will need to set additional permissions. Obviously
they need to set at least Reviewer rights on that calendar folder, but they
also need to set the Folder Visible permission on their top-level mailbox
folder.
In Outlook, right click the top-level folder in the folder list to the left
(Mailbox - Xxxx Xxxx)
Select Properties for Mailbox Xxxx Xxxx...
Select the Permissions tab
Add the users just like you did for the calendar folder and give them the
Folder Visible permission (last checkbox on the lower right of the
Permissions Window, under Other).
Select OK
The user that was granted access to this folder will now want to add that
mailbox as a secondary mailbox to their Outlook profile. On their system, in
Outlook:
Right-click their top-level mailbox folder (Mailbox - Xxxx Xxxx)
Select Properties for Mailbox Xxxx Xxxx
Select the Advanced... button
Select the Advanced tab
Select the Add... button
They can enter the person's name sharing the calendar as it appears in the
Address List
Select OK | OK