Prevent incoming messages on POA level

Hi Forum,

this question justs pops up and now I'm wondering...
Is it possible to prevent incoming messages for one Account on a POA level? I know GWIA can accomplish this via Class Of Service.
But maybe I want to disable a Mailbox and want to prevent icoming messages from internet (which GWIA can handle) AND from the same POA (which GWIA can't handle as the POA delivers the mail directly without GWIA).

I would guess some of you groupwise specialists would know that offhand :) I say "no" but not 100% sure