In LCM Subprocess Workflows (https://community.sailpoint.com/t5/Technical-White-Papers/LCM-Subprocess-Workflows/ta-p/75856#ProvApprSubprocess), it mentions the argument approvalAssignmentRule that can be used to customize the approval process.
The JavaDoc of Rule.Type has ApprovalAssignment as one of the enum values.
But what kind of input/output does this type of rule expects? I searched and find nothing on Compass.