https://webhelp.episerver.com/Commerce/1.1.2/Content/User%20Guide/OrderManagement/SplittingShipments.htm

You can use split shipments feature in Commerce Manager to create new shipments, add/remove items to them. Then add shipping method to each of them 

Hello Quan,

Thank you for your reply. But I am looking this through source  code on website side, just like given an example in link above. May be I posted my question in wrong area.

Thank you.

So you are trying to load the shipping method to assign to the shipment, or?

Hi Dipak,

Shipping method id and shipping method name is no longer under line item (they were obsoleted). They're now under shipment (as well as warehouse code).

In your case, I think it's possible to create multi shipments with different shipping methods, then "pick" line item to corresponding shipment.

/Viet Anh

Yes. I mean I am getting shipping method from ShippingManager

ShippingMethodDto methods = ShippingManager.GetShippingMethods(SiteContext.Current.LanguageName);
List<ShippingMethodDto.ShippingMethodRow> shippingMethods = new List<ShippingMethodDto.ShippingMethodRow>();

Now I would have to set IShipment for cart with ShippingMethodId, ShippingName  etc.

This should be enough (From Quicksilver)

        public void UpdateShippingMethod(ICart cart, int shipmentId, Guid shippingMethodId)
        {
            var shipment = cart.GetFirstForm().Shipments.First(x => x.ShipmentId == shipmentId);
            shipment.ShippingMethodId = shippingMethodId;
        }

You probably want to validate the cart after because the total/promotions might have been changed