[linux-audio-user] Audio interface full duplex

Hi, Konrad here, I am new to this list and about to build a serious linux box. We are planning to build a system that can send (serve) and receive mp3 streams at the same time using a multi channel interface such as an RME Hammerfall card. As I have about ten boxes running different flavours of linux but never even touched a graphical interface, I have gotten as far as running mplayer to receive one stereo feed and send it to an M-Audio Delta 44 from command line. I wonder if a) you can run several instances of mplayer and send their signals to separate outputs of the same I/O card and b) whether it's possible to run multiple shoutcast servers at the same time that get their audio from the inputs of that same card. I've heard of jackd but am not sure if it can do all this. The whole thing is meant to be run in a recording studio so it must be rather professional. Thanks very much for your comments and cheers, Konrad