Rule Time Tracking to include hrs

Currently Rules can only be influenced by the day, and I’d like to be able to set the hours. I have some projects that need very tight turnarounds by designers (2h, 5h, 10h), and I don’t want to manage it by hand due to the sheer volume of tasks coming in. Plus this is also running 24/7 which goes outside of my timezone, so it’s not feasible for 1 person to manage.