At this time there are no command line flags to run the player to select frequency as you suggest, but that is a good idea. We have added the request to our list of development tasks, but we may not get to it for a few months.
An alternative to this could be using a paid account with our Private Agent. The Private Agent basically installs an entire instance of our monitoring cloud behind your firewall, and then you can run all of our monitoring tasks behind a firewall. This options is much more expensive and sounds like it would probably be overkill for what you are looking to do. The private agent is able to monitor additional network targets such as VoIP systems, email servers, intranet sites, port availability and more.
https://www.dotcom-monitor.com/wiki/glossary/private-monitoring-agent/
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