looking for 2 domain, 1 site help

what I'd like to do is make all posts in category podcast use domain2.com and all other posts and pages use domain1.com

or another option is to make all post by a specific user to use domain2.com while everything else uses domain1.com

I'm stuck... can't find a plugin or an easy solution. I've been looking for hours.

Any help is greatly appreciated.

thanks