Repetitive ”randomly” assigning/selecting team members for a task based on previous number of selections/assignments.

[ciprinitu]

Hi everyone.
Here is my problem/project:
I have a team of 20 persons.
And just one task, which can repeat/occurs up to 100 times/day.
The first 3 members of the team must have „a kind of” priority (let’s say 20% more) in being selected/assigned to do that task.
Every time the task occurs/appear my excel file should choose „randomly” one of those 20 members to do it.

Allow me to explain „randomly”:

• Every time the task occurs, it should select randomly one of those 20 members BUT with ... let’s say ... up to 20% more chances for the 3 of them with "priority".
• On a monthly basis ALL of those 20 members should have „mainly” (not exact) the same number of tasks assigned. Yes it is fine if those with „priority” to have 20% more tasks than the other 17 but between this 17, the gap between least and most tasks assigned shouldn’t be more than 10%.

So, with each assigned task as described above, the number of tasks done for the selected member should increase and the total number of tasks done by each member is the key for „randomly” task assignment.

As an example: the task for the team members is to take a 2 minutes extra break form work.
I hope I was clear enough to describe my „problem” (project).

ANY help is more than welcomed (even if is just an small idea).

Thank you A LOT in advance.
Ciprian