Permission to see all Communications

Hi everyone,

I’m using ERPNext 15.

I have a dispatch server for emails. I use ERPNext and frappe for email scrapping, and send ticket, generate by the created communication, to my server.

My users can setup email account. To avoid these users to set this email account in parameters of my API user, I want to setup a permission to my API user for read all communication, and not only if my API user is creator.
So, I have tried to set same permissions on Communication doctype like “System Manager”, but I still can’t access to a communication not created by my user, or a communication created by an email account in my email_users list.

What permission can I do to authorize this ?

Thank’s