back dated discount/ rebate if a condition is met

Hi Experts,

We have a scenario where a vendor offers 2% discount/rebate for all Purchase orders if the total value of purchase exceeds a certain value in a year.

If total purchase value does not exceed the threshold amount, then discount is not provided.

Can you please let me know how we can map this scenario in SAP?

Can it be done using condition contracts? If yes, how?

Thanks in advance