ATP Hook for different ATP calculation

Hi All

I need some input about the use of ATP hook. We are using ATP based on Planning Output.

ATP checks the supplies in ASCP Plan and then suggests a date.

All is working fine.

However we have got requirement that for certain set of customers we need to promise based on Forecast.

For these customer orders if ATP request is fired, then it should check for the unconsumed forecast quantity in ASCP and then return a date.

Can we modify the results using ATP Custom hook for certain type of Sales Orders?

Please let me know if anyone has done something similar.