How to align your Analytics with time windows in Azure Sentinel using KQL (Kusto Query Language)

CliveWatson Great use of various sets of queries where time & day could be tuned. 

I'm trying to come up with a query which renders mean time to respond and mean time to resolve for weekly or monthly reporting, however the challenge I've is we only operate 9-5 PM weekdays only and this is messing up the stats for obvious reasons. Let's say incident is fired midnight and no one would pick it up till 9AM and when the stats are run for mean time to respond and resolve they would naturally be higher. 

Would you be able to help here!