AWS Security Groups Whitelisting

Hi currently I'm adding the IP's manually to security groups in AWS to monitor the status of specific servers behind our firewall and loadbalancer and well the whitelist seems to get longer and longer.

Does anyone know how to add the domain site24x7.enduserexp.com to a security group in AWS so I don't have to manually add new IP's when new locations are spun up or remove locations when one is retired? I can't seem to find a way to do it.

Any help appreciated!