You could do this with procmail, a rule like:
* ^From: email@example.com
And trash anything else with a procmail trashing everything else:
* ^From: *.*
Take note, I've not tested this, but from my understanding this should work. A few test emails should help to see if it actually does
As procmail processes recipes in order, if you have these in this order, it *should* work.
You might get spam if the person is someone like:
that you allow through, just an FYI. I don't know of an easy way to get around that, other than to use spam checkers and then filter the spam through first, then apply these last procmail recipes. See:
For more info on using procmail recipes.
One last thought:
~/.procmailrc (and possibly ~/.procmail/) is where these recipes go, this will only affect the user who has them in their home directory.