I have a WU id for my Davis station, and another for my Bloomsky. Bloomsky uploads data and pic. Once you get that going, right click on the image for the Bloomsky station and "Copy Image location". You'll end up with a link like shown by Paul.
Then you can add another camera with file location pointing back to a WU Image location. Associate that with your other station.
However, be warned. My Davis station camera pictures keep getting kicked offline. I have to frequently go back in and re-submit and wait approval. Apparently their weather cam product is so crappy, it won't even trust pictures on their own site. Mine has been waiting for approval again for over a week.