User Exit or Enhancement when copying determined batch in Production & Process Orders

Dear Experts,

VERY URGENT

I have a requirement that when determining batches in production order and process orders, the batches which are more than specified days (Ex:- 60 days) should be consumed first. I can say that the fields should be greyed out and the user should be restricted to make any changes in it. If the age is lesser than the specified batch, the users are allowed to make any changes in quantity within the determined batch.

Your swift response in this regards is highly thankful

Best Regards

Senthil Nathan Karunanithi