Masking MS Teams Service Desk Agents

Hello,

I would like my Service Desk agents to be more active answering questions in MS Teams, but what I would like to try and avoid are staff trying to contact those agents directly after the fact.  Does anyone know of a way where I can mask a group of MS Teams users in specific channels so that the name of the user is masked (ie shows Helpdesk instead of John Smith). 

Thx!