Right now we're allowing ticket replies by email, essentially to make it easy for clients. Agents can also reply by email but their replies will be added as an internal note. Fine.

However this has created some confusion for certain agents, thinking they were sharing their reply to clients that way.

I was wondering if there was a way to only allow email replies for clients/end-users and totally remove that option for agents and thus also removing the confusing "reply above this line" bit agents see in their email notifications?
(FYI: I've already added in our agent email templates a line a the top stating "do not reply by email, please login to the agent portal")