I'd recommend against announcing that the meeting is being declined because of a focus block. Someone will read that as "free time" and demand you meet anyway. Put 3-4 fake "meetings" on your calendar during the time you need, so it just looks like you're booked. If your company requires you keep your calendar public, call the meetings something gross like "vendor review" or "Finance and Engineering Integration: Overlapping Initiatives" and nobody will question it.