A customer suggests to be able to manipulate the last articles visbility.
If you’re communicating internally with your agents, you currently only can change the visibility of incoming mails to internal. However, you can’t manipulate the visbility of outgoing articles.
Even for incoming this only applies to incoming mails.
The customer doesn’t have all of his workers within Zammad as it’s not needed. Sometimes they still need to communicate with each others - agents use Zammad for that to keep track of the answers for the specific ticket.