I have 200-300 items from different vendors, whose products are also different. I would like to get Invoice nos. different for sale of items from different vendors. I currently making different invoices for for different products to same customer. Eg. I have products from Havells, Philips, Morphy etc. if same customer wants different products from all 3 brands then I have to bill 3 invoices with each invoice having products from same brand. I would like to get Invoice nos. having a prefix that depicts the items it contains for eg. PT/HAV/001 will have only havells items. Similarly PT/PHL/002 and so on.