Please help? Can I auto attach featured image to posts without images?

I have a number of RSS feeds and would like to automatically attach a featured image from my library to each feed (none of the feeds contain images).

The featured image needs to be the same image for all posts from a feed.

i.e. attach image 1 to all posts from feed 1
attach image 2 to all feeds from feed 2.

[duplicate of http://wordpress.org/support/topic/please-help-can-i-auto-attach-featured-image-to-posts-without-images?replies=1 One post per topic, please]