Remapping would mean that that user would have the four directories in their own home directory. Your website would serve its data from that user's four directories. You can't give away existing directories in your own home directory.
You could use subdomains instead, but subdomains tend to not we well-incorporated within the main domain. Remember that subdomains and subdirectories are very different concepts. I'd stick with the remapping if it's really all part of the same website.