Hierarchy Creation

Hi,

I want to create 4 level Employee hierarchy from an Employee flat list. The employee-flat list has all employees, but I only need employees under one particular function. (let is assume 30 employees of one specific function out of total 100 employees). There are no departments or cost centers available. The only identifier is Emp code and Employee Manager code. What will be the best approach to create this hierarchy?

Level 1 Employee Code will be the Employee Manager code for Level 2. Level 2 Emp Code will be the Employee Manager code for Level 3, and Level 3 Emp Code will be the Employee Manager Code for level 4

Please refer to the attached screenshot for more understanding.