How to alert if a Cisco device has not sent any logs via syslog to Splunk in X hours?

Hello, Currently I have 50 Cisco devices sending logs via syslog to Splunk and use the Cisco App. Trying to figure out how to create one alert that can fire once or twice a day, that will report all Cisco Hosts, that have not logged during that time. Could not find an example to start with. Thanks Brian