Unable to add custom LOV value in the Population Type in "Change current task"

Summary:

Dear Team,

Our Client want their HR user to "Share and Release" performance document step for all their employees who were grouped as per their custom criteria.

Like in our client system, all employees have been grouped into 7 groups. Like each group are list of employees who are coming under Hierarchy of CEO-1 employee. Like that, our client have 7 CEO-1 employees. And so, they have 7 different groups of employees.

And expectation is, HR should be able to "Share and Release" performance documents to all the employees of one group in one go.

Like in the navigation, My Client Groups -> Performance -> Mass actions for Performance documents -> Actions -> Change current task -> Entering current and new task -> Selecting Population type -> In that, by default we are seeing 4 options i.e. Employee, Manager, Department, Business unit.