Time Tracking between 9am to 5 pm

I’m looking for a way to add a condition to count the time spent on a single task so that the time can only be counted between 9 am and 5 pm. Outside these hours, the time should be automatically stopped.
I created an additional column with the formula: AND(Hour(Now())>9,Hour(Now())<17) which returns True or False. Unfortunately, I can’t use this column in automation as a condition.