http://secondlife.com/vote/
Proposal 73 Deatails
Hitting "busy" is great when you want to be completely alone, but if you want to focus on on chatting with a group, especially if not all are in the same sim, there are no tools.
There are tools to chat in groups, but not to block other IM's while doing so. Also if a "Group chat" is being created, everyone involved should know who is listening via a specially labeled IM window should pop up. Currently conference IM's don't do a great job of explaining who you are talking to.
Somewhat similar to a conference IM, you should be able to make a folder of calling-cards and set to "ignore all but these".
Possibly could be a PIE menu choice with a "stand" like cancel (improved "talk to" anyone?). Any person who joins would need to know that contact with others will be cut (ideally they could join in with or without muting others).
I feel dance bracelets have the right model
You can add and kick people form the 'dance'. Equally, you should be able to add and kick who you are chatting with.
Example function:
Tom needs to chat privately to Dane and Jick, who are present, and Harry, who is in another sim.
Tom Right clicks on Dane and hits a pie menu.. lets say "confer" (9 letter limit no?) It's important at this point that the user know, with possibly a warning, that they are muting all other communication.
Dane gets an invite which explains that other contact will be cut if Dane joins the conference. If Dane hits accept Tom and Dane can now chat privately while being undisturbed by others.
Tom then clicks on Jick to add Jick to the conference, Dane gets notice that Jick as been added.
Tom can then select a calling card and add Harry to the meeting. Dane and Jick get notices that Harry has been added.
Each participant's title has (Meeting) ..or such.. added to it.
Anyone IM'ing Tom, Dane, Jick, or Harry receive notice that they are in a meeting.
Dane leaves the meeting and Tom, Jick, and Harry all get notice.
When the last person leaves Tom is notified if he wishes to stay in "busy" mode or go back to normal.
Many details here, but the main idea is to talk with a few people while in "busy" mode.