How to set Min Amount if there are Price breaks

We have a Modifier  for a Product with the following price breaks

Quantity range     -     Price

        0  - 5000             $2

   5000 - 10000            $1.5

100001 - 99999999      $1

This works fine but now how to make the order line minimum Amount to be $2500  if the line amt is less than 2500

Thanks,

Satish