Item grouping and lot no on a single line

I would like to have the items group in a single row, that is not to complicated, however, each items has a lot number (serial) and in the column near the item number, I would like to see these serial number one after the other, on a single line, separated by a comma.à

If a customer order a quantity of 2 of a specific item, the software I use create 2 lines because of the serial number attached to it, and on the quantity column it write 2 times 2 so my invoice is out of balance, this is because of the serial number.

Example:

Item                 Description          Quantity             Serial number

1234                 Item 1234                 2                   50012

1234                 Item 1234                 2                   50019

I would like to see this:

1234                  Item 1234                2                   50012, 50019

The item and the serial number is in the dataset "ShippingBill" the fields are "Item" and "Lot"

Can you help?