Completely disable DNS/Mail Service

[WeDoHosting.com]

All of the resellers I've setup with an account in Plesk are using the server as their web server, mail server, and DNS server with the exception of 1 reseller. This 1 reseller is using a separate server for their mail and DNS, they are only using Plesk for the website hosting.

Is it possible to completely disable DNS and Mail only for this 1 reseller? Or somehow modify their account so that each time they add a new domain to their profile, that Plesk automatically disables the DNS and Mail services for the domain?