Can ColdFusion upload a file to a different domain?

We have a client that has three domains for three different properties (we'll call them a.com, b.com, and c.com), but wants to administer all the content through one main admin on a.com.

I'm not having a problem with information that's contained in databases, especially since all the domains are hosted on the same server. My problem is with the extremely simple photo galleries on each domain (and by "simple" I mean the images names are merely retrieved with cfdirectory.)

Is there a way to upload an image from a.com/admin to b.com/images/gallery? I've never had to do anything like this before and can't seem to even retrieve the directory contents of b.com/images/gallery from a.com. Would all this require cfftp instead?

Thanks!