RainMaker does have the ability to show on the Calendar when an employee is going to be out for a period of time.
What you are going to want to do is go to your Calendar. Select Resources at the top of the screen.
This will bring up your various employees.
Select the employee and the beginning of the time frame desired.
The appointment box will pop up. Go to the Appointment Type and Select CLOSED. Fill in the information necessary after that and the duration of time they will be out.