Hi,
This feature is only available in higher end systems - I'm sure there's a Sage product that will do what you need.
You can filter the Inventory Reports menu - I.E. you could filter for 'Starts With' DEW or POR or DEL or B-D, open the report in Excel, copy, and paste into an Excel template. You might even be able to copy and paste into the Purchase Order screen (I didn't try). If you issue 1 purchase order a day to 2 or 3 suppliers this would be practical.
What isn't in Simply to make this automatic is the sort of features where you would record primary and secondary vendors, prices, quantity discounts, package quantities, weight, cubage, freight rates, terms, etc. and it would automatically calculate the best mix for an order. That's where SAP (or the Sage equivalent) comes in.
It's probably not impossible to use one of the 5 'extra' data fields for an inventory item as your vendor if it's always the same vendor, and build an Excel report using ODBC that would feed the data into a purchase order. I'm sure a third party vendor could put that together for you if you need it.
Using TLAs in your part numbers to identify the manufacturer, building reports for each vendor, and putting all the reports into the Report Centre so you can run them with one click, then manual keying from these reports might be a good start too. It may be best to keep a human in the loop.
Randy