multiple condition & multiple solution in excel

Please help if possible.

I want to create a dashboard in excel, where I want to calculate the total sales of the agents in my shift. But the problem is that I want to calculate multiple agent's sale score in a single case as well.

Conditions:

• If in a single sale, there are 3 agents, the sale would be divided among the three with the 3rd person getting 50% of the sale amount and the 1st and the 2nd person both getting 25%.

• If in a single sale, there are 2 agents, the sale would be divided among them equally.

• If a single agent cracks the sale, the amount would belong to him alone.

Now how would I put a formula where these things are calculated automatically?

e.g.:

Agent 1     Agent 2     Agent 3    Sale Amount 
Adam                                $100 
Jack         Adam                   $100 
Nick         Vince      Adam        $100 
Vince                               $100 

According to this, the amount would be as such:

Adam: - $100 + $50 + $50 = $200
Jack: - $50 = $50
Nick: - $25 = $25
Vince: - $25 + $100 = $125

This is the kind of result I want but want to get it done automatically as soon as the sale is entered. Anyone know how to achieve it through formula?

Thanks in Advance!

Hope this help you out. I tested it and it appears to work.