anyone know how to silent group chat notification?

in the old BB OS, I can set the notification to be silent for group ONLY while BBM PM will get notification, so any group pictures, chat, etc will be silent, i only hear ping from BBM PM.

now I can not find setting to silent the group chat. If I disable the group chat on hub, it will not show on the hub (which I want), but i want the group chat not to notify me or ping me for updates.

any tips how to achieve this like the old BBM?

Thanks.