Billing rule set-up

We are a professional services company and we have a unique billing rule that we have to set-up, but I am not sure how to do this. We are still in the implementation phase of Acumatica.

The rule that I have to set-up is the following:

If the employee works 5 hours or more a day, then we would bill a fixed rate of $5,000. If they worked less than 5 hours a day then we would bill their time at their “normal” billing rate.

Anyone have an idea on how to set this up?

Thank you.