[alsa-devel] Can I control volume of each virtual device?

Hi, all: We are on a project using alsa. There are three applications will use the sound card, but we only have one physical card. My plan is to create virtual device for each application. How I'm gonna control the volume of each device, which interface to use? I want this feature because when one application need to be exclusive, it can mute the other virtual devices. Any comments or advices is welcome. Thanks

BR Feng