Pay type that adds 1.50 per hour

One item we are working on right now is to pay ERT $1.50/hour for being on the team. This would work similar to pay increase for "Trainers" and be paid in the same manner (only during regular scheduled shifts and not during training events, Administrative leave, vacation etc.). Team members training for regular work duties would go to the Department Business Unit.  The $1.50/hour increase would be charged to 1405 business unit and remaining wage would go to their home unit.

Any help out there on how to make this work in 9.1 payroll module Enterprise 1  - Or all the considerations.

I'm thinking about the overtime calculator - excluding these wages.  Maybe just a pay type that has a flat $ amount $1.50 excluded to overtime, then this entry would be generated through payroll?