I'm trying to get clarification on how I can use dynamic DNS with my registered domain together for a specific configuration. I have a domain registered with Dynu which is scottsumner.net

I have three homes located in Colorado, Tennessee and Montana. I want to be able to access each of these locations using the following subdomains:

co.scottsumner.net
mt.scottsumner.net
tn.scottsumner.net

Each location has router that supports dynamic dns and I want to ensure that the DNS entries get updated when/if the ip address change.