SSFF HR Connector "Separate Effective And FutureDated Employees Endpoints"

Hello,

As stated in the "Starling Connect Hosted - One Identity Manager Administration Guide" about the flag "Separate Effective And FutureDated Employees Endpoints":

"The default value is false. When the value is set to true, the employees would be separated into two endpoints - the effective dated and future dated."

On the basis of which field are employees separated in the endpoints?

Thank you, Lucrezia