How can I stop affiliate commission for over one year

[zahidfact]

I want to stop affiliate commission for if user buy over one year plan. Then affiliate get commission just from one year price.

Ex. affiliate commission 10%.   Product price:    1 year "$ 20",      2 year "$ 40",         3 year "$ 60".

Now If user buy "3 year plan" then affiliate get 10% commission from "1 year $ 20". affiliate get "$ 2".

 

I can't find like this option on affiliate setting. I think If add like this option it will be good. See: 

 

 

Thanks