Actually there is no question where set of employers are same in all 5 companies. If all 5 companies are working as a group company i.e. one parent company and other 4 are subsidiaries declared by company secretary then transfer of employee from one organization to other follows with transfer of equity fund from one organization to other organization gratuity fund. An equity amount of 3.5 years can be transferred from A company's gratuity fund to B company's gratuity fund where employees group joining date will be considered at the time of transfer. Employee will be eligible for total years of service at the time of his/her resignation.