Team Role Membership
Team role membership determines to which roles team members are added when an incident occurs that is assigned to a given team. This helps to avoid manual intervention or confusion in the middle of an incident, and automated the process of assigning roles.
When a team is attached to an incident, the named team member will be automatically assigned to the chosen role.
To add a new team role membership, do the following:
Navigate back to the team dashboard page, then click the team name as shown in the prior example. You will be taken to the team details page. Click Add New Membership.

On the new membership details screen, select the user and desired role for that user as shown below, then click Create Membership.

Additionally, a User can also be an on-call schedule from your alerting solutions like PagerDuty or Opsgenie. This will automatically add that user to the incident channel if they are associated with a role. To page them you can create a Workflows and set the Conditions to match your specific teams.

