Please google for qmail-spp patch.
It allows to filter mails on the 'from' and 'to' content base.
I am not sure if the filter you are looking for is available but for instance I am using this patch to block the mails sent to some local accounts which should be available only for local users.
I am pretty sure you will be able to easily create your own filter if you have some programming skills.
Or maybe you will find the ready to use filter you need.
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