How to Add More Employee Types (other than the available) in Workforce Module in EPBCS

Summary:

We have enabled Workforce module for "Employee and Job" as granularity.

Now the provided Employee Type members are Regular, Contractor, and Temporary. These three employee types are not enough for us and we need to add more employee types to meet the Business requirements.

We need granularity as "Employee and Job" as both Employee and Job are required as level of granularity.
The system isn't allowing us to add more employee types as the account (OWP_Employee Type) is controlled by a non-editable smartlist.

Could you please help?

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