It is possible to forward messages including attachments by clicking the Gear icon in the email. But when you forward the message to someone else, it will have the same ticketnumber, and therefore, the different people will be able to see each others communication.
It would be very helpful if it is possible to forward a message as NEW related ticket. So it will have the relation to the current ticket, but there it will be possible tp have 2 conversations with 2 different people about the same subject.
Here this happens a lot. We receive questions, and we need input from a supplier. So we forward the message to the supplier, but it is not desirable that the customer can see the complete communication with the supplier (and sometimes likewise)