At this time it is not possible to create tickets and select the From email address from which customer communication is done. The default workspace email address is then used.
This does seem to be possible for conversations though. There you can select the email address from which you want to send the outgoing email to the customer.
This should also be possible for tickets.
At this time a conversation needs to be created with the outgoing email to the customer and after that the conversation can be turned into a ticket.
In our environment our Operations teams monitor our systems, create a ticket when they see an issue and then the 1LS teams contact the customer.
But this doesn’t work, because when 2LS creates the ticket, the communication 1LS sends is sent from the wrong From email address.