How to find out if Amazon itself is selling an item through API?

I am using "GetLowestOfferListingsForASIN" MWS API to get the lowest prices sold in Amazon for an ASIN. My requirement is to find out if the lowest price is being sold by Amazon itself. Since the API is not returning any seller ID so I am unable to determine who the seller is.

I know that "AnyOfferChanged" subscription does return seller IDs however it notifies only for items that I sell. But I have lots of ASINs that I do not sell and I still need there price at which Amazon is selling.

Could any one please tell me if this is possible through the API or if there is any other method.

Thanking you all in advance.