mute notifications/highlight icons from a particular user, across all servers

Hi!
It'd be great if I could r-click on a user and then mute all notifications related to that user across all servers. I have a friend, let's call them Able, and Able likes to post _a lot_. I don't want to block them, but by the same token, I don't want to see the little "this server has had activity" or "this channel has new messages" icon messages when Able posts. I'll eventually see Able's posts when I happen to surf to those channels, or I'll see server/channel highlight notifications if someone else replies, which is fine.

Or maybe this would be better implemented as a per-server thing, so that people have granular control. (It'd be nice if I could do all servers at once, though. :) )

I like Able, but well, they're not going to be receptive at this time to post less, and besides, their enthusiasm shouldn't be squelched. Thanks for considering my request!