Filter generated nodes by the generating feed

I have created 2 feeds (both been created by a special "feed creater" role user). They are successfully brings RSS and creates story nodes.

My need is to make 2 separated views, each of them selects and displays all stories created of a specified feed.

I tried first to make the generated story to be tagged with a fixed taxonomy term. I could not succeed.

I then tried to see if I can add in each view a field with the nid of the "parent" feed of the story, that is, the feed (one of two) which the story was generated after. I could not find such.

Using devel/render I have found that there is some feed_nids array holding the node of the parent feed. But, alas, I could not find its representation in the fields of the view.

Is there anybody who can give me a clue (or answer...) how can I do this. Please note that I do not want to make an extra dummy user dedicated to each feed which I need to create (this, of course, would easily solve the problem by filtering be uid).

Any help will be appreciated. Thanks!