How to purge Process Management History for a specific Scenario/Year/Period?

Hi, We're using a scenario to run a Rolling Forecast process that span across multiple years and the idea is to restart this process every quarter with a clean sheet so users are forced to reevaluate the forecasted periods. It's no big deal to clear the financial data, but as we use Process Management to control the closing process, we reset the Process Level to “Not Started” before the next quarterly Forecast begins. The Process Management History from the past is not needed and is just in the way, once the new cycle is on.

So the question is: How to purge the Process Management History for a specific Scenario/Year/Period?