Directing a subdomain to another WPMS before it reaches original WPMS network

Can anyone give me intructions on how to beat WPMS to the punch?

I have a WPMS network setup with subdomains. I want set up another WPMS network on a subdomain now. So I need to direct the subdomain to a different folder with a different WPMS network before it reaches the first WPMS network on the main domain.

I have decided to do this to separate members into different logical groups.

My domain chiropractor.com is set up as the first WPMS network using subdomains. I have decided I only want chiropractors as members for the sites on that specific network so they can join and have automatic access to all the sites on that network that are intended for their use.

I want to set up one subdomain for companies that sell to chiropractors but they have a completely different set of needs so I want to put them on a totally different network. Which means I need to direct a subdomain like companies.chiropractor.com to a folder with a totally different WPMS network. To do this I have to direct the subdomain to a different folder with a new WPMS network install (before the request reaches the first WPMS network on the main domain Chiropractor.com). I plan set the new network up using subdirectories. Example: companies.chiropractor.com/alpha-chiropractic-supports

So my question is: using cPanel or Web Hosting Manager how would I direct the subdomain to a different folder before it is handled by the original WPMS network install?

This would be the same situation if anyone wanted to direct a subdomain so they could have a static web site or use anything other than Wordpress.