Is it possible to block a user in IM+ ?

I can't seem to figure out a way... I leave my computer logged into AIM while I'm at work, and put an away message up when I leave for the night.... --That way, if people IM me, and I'm still logged into IM+, and have my default away message up in IM+, then the message goes to both my PC at work and my iPhone. When I'm at work, I take my away message off, so the messages only go to my PC.

My question is in regards to the annoying "AOL System Msg" which randomly tells me (on both the phone and the PC) that I'm connected in two locations. I am able to use a plugin for Pidgin at work to block that message (since AOL doesn't allow blocking that screenname), but I can't figure out how to stop the message from going to my iPhone.

I know I can turn on the "block users not on buddy list" in IM+, but I don't really want to do that, because if someone IMs me that's not on my buddy list will just think I'm ignoring them!

Any suggestions? The reason I continue to prefer IM+ is because of multiple networks it connects to (AIM, MSN, Skype, etc) AND it does PUSH!