Creating WWW branded sites for domains used in multi-domain

Hello, I've setup Multi-Domains and love the flexibilty.

After creating the wildcard DNS all the functionality works correctly, but since my * and WWW record are still pointing to the old IP on the server, those records are still going to old pages.

As far as I'm aware, I can change those IPs to point to my Multisite IP and they would work like the primary domain does.

However, this made me realize that I would love to use the "www" version of those domains as a landing page that could be specific to a niche audience.

I.e., my primary domain is hyper-wp.com and a generic web site builder. One of the multi-domains I use is writerwebs.com, which I am focusing on author web sites.

So my question is: Can I configure http://www.writerwebs.com as a landing page in the network that is different from http://www.hyper-wp.com or any other domains, yet still on the multisite network so a user could click to register or login from that landing page and experience the same functionality?

Sorry for the cluttered, long question - just trying to explain it as best I can. Thanks!