Enhancement for need of Stop Batch relesase if there is any Open Defect for

Hi Experts,

I am new to Enhancements.

I have a requirement -

 Enhancement which will be used by to stop Accept UD if there is any open notification for material, batch combination. 
This development will also check if there is any open notification for batchu2019s consumed to produce good for which UD is happening

Program will run at the time to UD or change UD. If there is any open notification for batches or any open notification for the batches consumed to produce batch then do not allow user to populate u201CAu201D UD code.

In enhancement where program will search for batches consumed and if there is any open notification then stop UD .

Requiremnt-

1. When user is doing disposition and UD will have valuation Accept -

-Program should check if material + batch for which UD is happing that any open notification

If yes then UD with Accept valuation should not be allowed Give error message u201C Open Notification XXXXX for Material XXXX BatchXXXXX exist.

-Program should also check if any notification is still open for materials /batch consumed to produce batch for which UD is happening same material and batch any notification is still waiting for completion

If yes then UD with Accept valuation should not be allowed Give error message u201C Open Notification XXXXX for Material XXXX BatchXXXXX exist

Note:- this error should be come before VLMOVE will do any Material to material transfer

Note:- this error should be come in QA10, QA11, QA16, QA17, QA40 and QA41

Please help i am not able to figure out from where should i start.