Ticket Subject Unchangable

We would like the ability to be able to set the subject of an incoming chat ticket as we would like it to be.

Currently the tickets are all "Conversation with..." followed bu their name or visitor number depending if the information is provided.

We would like the ability to change this as we see fit, maybe even the ability for this subject to differ by department / group.

This would make it easier for us to distinguish which chat conversations belong to which team.