Hi,
Talk to LIC,they might be having a group gratuity fund in which you maintain certain amount with LIC,and since your prediction is not many employees will be there, annually eligible for gratuity so you need not maintain lakhs of rupees with the fund. However you need to estimate how much approx. may be your gratuity liability per annum. As I told , in my earlier company (an IT company) we had kept around a lakh rupees to begin with, as we were very sure not too many employees will be crossing 5 years.
Thanks
Geeta