@sburger  Yes, it is possible to add multiple vendors to a stock item.

Below screenshot is a sample reference that I have added multiple POlines to a Purchase Order. 

Hopes this helps you to add the multiple vendors to a stock item. 

@sburger  Since it is having on handy sharing the import scenario, which you are looking for. 

Just tested and it is working as expected! Hope this helps!

Let me know if you have any queries.

@Naveen B Thanks for your answer.

Our system is set up so the item class populates the purchase unit field but when I upload 2 vendors it tells me purchase unit cant be empty but when I add PU  to the scenario it says can’t upload duplicate even thou its not the same.