How to define PPR approval rule by payment amount?

Hi All,

I am trying to set the PPR approval flow by payment amount.

For example, I submitted 2 PPR :

PPR A contains 3 payments and their amount is 50, 40, 10.

PPR B contains 3 payments and their amount is 40, 40, 20.

I want to set a rule that if the single payment amount is more than 50, assign to Tom , else assign to Jerry.

So Although the total amount of the 2 PPRs are the same, the need to assign to different person.

May I know how to achieve it?

Thanks in advance!