How to assign Individual User as Primary Preparer/Reviewer and Team as Backup?

Summary:

Hi All,

Requirement from Customer: For each reconciliation profile, the customer wants the workflow assigned as below:
Primary Preparer: Individual named user
Backup Preparer: Team (group of users who can take over in the absence of Primary Preparer)

The same pattern is required for the Reviewer role across all review levels:
Primary Reviewer: Individual named user
Backup Reviewer: Team

Content (please ensure you mask any confidential information):

What we tried:

In the Profile → Workflow tab, we attempted the following:
1. Assigned an individual user as Primary Preparer → tried to assign a Team as Backup Preparer. Not able to achieve this combination.