Summary 

Currently, the Escalation Rules allow configuring conditions as:
1. Notify admin(s) of team
2. Notify user(s) of team
which is to notify team members in an escalation policy according to their role, however, there is no option to configure such an escalation rule for a Custom Role defined in Opsgenie. Allowing custom roles to be included in the escalation policy drop-down options would be helpful. This would allow for multiple layers of escalation within a given team.

Workaround

Ability to select custom roles as an Escalation rule condition for Escalation policies as below:

Notify "Custom_Role_Name" of Team