You can set a question to private when creating the question in a review template.
How to Create a Template
Step 1: Navigate to the "Admin" panel found on the top navigation bar
Step 2: Click on "Reviews" found on the left Administration panel
Step 3: Click on "Templates"
When you are creating the template, you will see the option to mark a question with private by selecting "Restrict Visibility". This means that only the manager and the admin will see the response to the question regardless of the review's deliverable visibility settings.
This gives you the option to set up a review cycle so that a reviewer's feedback is mostly shared with the employee, but still have one or two questions where the responses are only shared with the employee's manager and the admin.
Here is an example:
If the deliverables were set to share the manager review:
And you added a private question in the manager review template:
The manager will see the question when filling out their review:
The admin will see the response that they provided:
However, the employee will not see the question or the response when viewing their review packet. They will only see the manager's responses to the non-private questions that the manager responded to.