How do I send an escalation mail to all agents of a group if a ticket is left unattended for more than one hour?

You can configure a Supervisor rule by configuring the below conditions in order to trigger the escalation email to all agents in a group. Navigate to Admin-->Supervisor and create a new Rule which would check for the condition “Hours since the ticket created greater than 1” and add an additional condition such as “Agent is None” and another condition to check for the respective group. In action, please choose “Send email to group” and choose the respective group and type in the content that needs to be sent.