Not sure what platform you use to send webhook signals to TradersPost...

I use TradingView which allows you to schedule or pause alerts/trading signals with the click of a button. I also use the Pine Editor to program logic directly in the indicator that is generating the alerts. For example, if company reports earnings in next 7 days then do not send alert; trading will automatically resume once condition is no longer true. You could program your indicator to accept FOMC or other blackout dates as input and if today is one of these dates, then don't send alert.