Resource Alerts for Assignment Projected End Dates to go to Assignment Manager not primary manager

Summary:

I have created a resource alert for all approaching projected end dates, but I need the alert notification to go the relevant assignment manager, not the primary assignment manager (unless it is for the primary assignment). The alert notification is pulling through all the correct details for the correct assignment but I am not able to find the assignment manager for the alert notification.

Content (please ensure you mask any confidential information):

${assignment.AssignmentManager}
Mail	${assignments.AssignmentManager.WorkEmail}

Message

Format HTML Subject Projected end date of worker assignments approaching - ${emps[0].DisplayName} Group By ${AlertUtils.empManager(PersonId).WorkEmail}${emps.PersonNumber}