What's the listener with Skype Java API to get Group message?

Question

I search how to have listener like ChatMessageListener but for groups... For this I use skype java api 1.6.

So I want to have this:

@Override
public void chatMessageReceived(ChatMessage arg0) throws SkypeException {
    ...
}

@Override
public void chatMessageSent(ChatMessage arg0) throws SkypeException {
    ...
}

But it's not working for Skype Groups :(

So how to have this for listeners of Skype Groups?