If an out-of-the-box integration between SAP S/4HANA Cloud and another SAP solution is not available, you can use custom CDS views or integration tools to build your own integration. Unrestricted firewall and Infrastructure as a Service are not relevant for this scenario.

When configuring phase controls for maintenance orders, you need to perform the following steps:
Assign phase control codes to an order type. This allows you to define which phase control codes are valid for a specific order type and how they influence the phase progression.
Define phase controls using the SSCUI. This allows you to create and maintain the phase control codes and their attributes, such as description, icon, color, and blocking indicator.
Maintain phase control codes for order headers and operations. This allows you to set or change the phase control codes for individual order headers or operations using the Manage Maintenance Notifications and Orders app. Reference: SAP Help Portal - Phase Control for Maintenance Orders

A planner group is an organizational unit that represents a department responsible for central maintenance work preparation. A planner group can be assigned to a maintenance planner, a maintenance notification, or a maintenance order. A planner group can be used to group notifications or orders by work centers, locations, or responsibilities. Reference: [SAP Help Portal - Planner Group]