Assign random number (RANDBETWEEN) equal number of times

Okay, so I have the following:


Week Task Name
week1 TaskA
week1 TaskB
week1 TaskC
week1 TaskD
week2 TaskA
week2 TaskB
week2 TaskC
week2 TaskD

I want to randomly assign names to a task. I have a group of names, each name has its own number. So now I can use RANDBETWEEN to randomly assign someone to a task. However, I want everyone to be assigned to an equal amount of tasks, I don't want person A do be assigned 5 times and person B 1 time. How can I ensure that each random number gets assigned an equal amount of times?

Edit: Also, the random number has to be fixed. It's no use when one day Task A has to be done by Joe, and the next day by Mark.