answer assigned emails without access to inbox

We want to assign emails to our employees and our employees should now be able to reply to these emails that have been assigned to them. HOWEVER, the employees should not have access to the inbox. They should really only be able to see the emails that have been assigned to them. They should reply with the same email address.

Example:

Team leader receives an email from user on the address info@email.de. Employee does not have access to the inbox of info@email.de and cannot see the email from User. Now team leader assigns the email to the employee. And now employee can see the email and should be able to reply with the email address info@email.de. The employee still should not be able to see the inbox.