Dear Amar,
The entire information furnished by you regarding the proposed move of transfer of a particular process/operation with the existing employees in the organization after their resignation with the assurance of fresh appointment in the other organization should most probably by word of mouth and not by any written communication. If so, certainly, this is a sinister motive of your present organization to circumvent the provisions of section 25-FF of the Industrial Disputes Act,1947 pertaining to compensation to workmen in case of transfer of undertakings.
The resignation from the present organization and fresh appointment in the other one as well, if any, based on the strength of such oral assurance would nullify the resignees' claim for continuity of the service before such resignation and any service benefit like gratuity accruing on the basis of a minimum qualifying period of service.
Therefore, do not accept the proposal and resign your job. Unless you are formally transferred to the other organization with continuity of service with the latter's acceptance, your service in the transferred organization would be a fresh one only. When your service falls short of 4 years and 240 days in the fifth year on the very date of your resignation, you are not eligible to claim statutory gratuity from either of the organizations. It is better that all such employees jointly make a complaint to the local Deputy Labor Commissioner.