Get register your company under Mathadi act. Enroll your existing workers with the board, who are handling loading/unloading work. Pay them regular salary (min wage act applicable), and pay 33% to the board. They will take care of e.s.i. / gratuity / bonus / p.f. etc. (You will save on - 20% on bonus + 13% p.f. + 4.75% e.s.i.+ gratuity, by doing the same.)
No responibility on the company.
Since these may be your regular employs, you may be offering them certain facilities which at present you are offering to them i.e. spl rate for tea/snacks/lunch/transport arrangement etc, you may continue the same.
You have an option to pay the salary through the board, or directly to the employee and 33% to the board.
No other liabilities. If possible, you may include your other employees also who are engaged in packing/stitching/filling operations. Employees who are involved in manufacturing process on machines/ plants should not be registered.