Invoice Event restriction from billing again after credit memo generation

 Hi Guys,

Please advise on the below scenario:

I have created invoice event and approved/released/interfaced to AR. Then i canceled the invoice and it generated credit memo as well as it has set the corresponding event to unbilled status i.e. the billed flag in event window is removed. ( This is standard functionality as per userguide)

However, i do not want that this event should be billed again, but the next generate invoice process will process this event and will create draft invoice. How to avoid this?

One method is to keep this invoice on billing hold; but i want to know if this can be automated or restricted?