Webmin Linux Firewall Refresh

Webmin allows me to put domain names into the firewall rules (e.g. source IP). When the rules are deployed the domain name gets translated to its corresponding IP address in iptables. Because these domain names are dynamic IP addresses, iptables needs to be refreshed periodically in order to pick up any address changes. Is there a way do automate this in Webmin so that iptables gets refreshed every few hours or so?