How to Reject an EDI Demand if total order value is less than $100

Hello,
We just implemented EDI a month ago and of course, we are still on the learning curve. I recently found out that we have an agreement with one of our trading partners that they can’t place an order if the total order is less than $100. I can write a BPM at Order Entry but I was wondering if we should reject it at Demand Entry. What or how would you recommend us doing this? Any help will be appreciated very much. Thank you.

Epicor 10.2.200
Accept if no errors

Perhaps you can develop a BPM in Order Entry to send an email alert to Sales or Customer Service team to inform that order value is less than $100 and put order on hold. Then they can call customer and decide to proceed with that order or not.