How can I stop employee seeing a journey till their task is available (task 4)

Summary:

I have a requirement for a journey to do with Honorarium payment, the first 3 steps are for the manager and we dont want employee to even know they are being considered for this payment, then they want a task for manager to upload a confirmation letter and employee to view it. Issue is soon as I assign the journey to them they see if and the letter task even though its greyed out and they can see name of the journey. If I assign it to myself as the manager I only see the task for employee (as system