From now on you can view and comment not only in your support tickets, but in your colleagues' ones in case you are in one and the same "Organization".
Go to the Service desk administrative section, create a new Organization and add users.
By creating organizations you can create groups of users:
People who are added to an Organization can view and comment in each other's support requests in the customer portal.
You can create an unlimited number of organizations, uniting various users.
The same users can be members in multiple Organizations.