Current version of VarAC allows to address a broadcast message to ALL, or to a single call sign. It should be fairly easy to add an editable "group nickname" to "My Information" tab in Settings, and to allow the broadcast messages to be addressed to holders of such nickname. This way we could have multiple "broadcast groups" operating at the same time, without interactions between them. What a great way to chew rags (:-)). If each message carries the real sender's call sign, the FCC should not have problems with this solution.
73s, Marek sp5isz