Custom Colum using an if statement to compare dates in a grouped table and sum values

Good day all,

for each row in the main table I need to sum the hours colum in the nested group under the Runs and tools column. Any help is appreciated.

I belive I need an if statement in a custom column.

custom column = if(table.starttime >= Min Created on && table.startime <= Max Created On, sum(hours)

I know this code is not anywhere near correct i am just trying to explain what i am after.