Partial Feed Option?

I found this plugin whilst trying to overcome issue where google merchant centre disapproves all of my variable products, as it thinks the price wrong (it takes the lowest price).

With this plugin, when creating a new feed, I notice it exports every single product from my store. is it possible to create feeds for just some selected products.

e.g. some products might be out of stock, on back order or discontinued so have no price. Google merchant centre returns errors for all of these products. I would rather just leave them off the feed.