This is possible via an InsightConnect workflow built from a custom alert trigger today see here, or by writing a custom script against our query API to essentially query for the data you desire on a regular interval, running a groupby(source_ip) for example, and then in the script you would check if the IP address appears more than X times. If so, trigger a log message to log search.
I have an example working script if this would be something you wish to explore, written in Python.
Also, if you wish to learn more about InsightConnect, see here https://www.rapid7.com/info/soc-automation/