To stop BFB print being sent to a customer after the site becomes invalid

Summary:

We have BFB enabled at the ACCOUNT LEVEL at the customer master data. Note that we have certain customer sites which are not in use and became invalid where no transactions are being entered for which we don't want the BFB statements to be sent.

Content (required):

Let's say we have a customer with 3 sites and as we have BFB enabled at account level, eventhough we have disabled BFB for 1 of the 3 sites, it still sends 0 dollar BFB statement to the customer even though there are no transactions on that particular site.

Also, let's assume if we have all the 3 sites that are not in use and has become invalid, in this case if I disable the BFB for all the 3 sites, then it is not sending any 0 dollar BFB statement to the customer.