Multiple Audio Outs?

Ok, so here's the deal. I use my MacBook in my band. I'm the drummer and run headphones out so I can hear a metronome. Well, I want to Utilize a rockband drum kit as well with Reason to add MIDI patches to our sound since the beat is now exact.

Here's my problem. If I run the sound from Reason out through the headphone jack (to the audience) I have no where to plug in my metronome privately so im the only one that hears it (through the headphones).

Is there any audio device (Preferably USB since my macbook does not have firewire) that can have two separately configured audio outs? Where I could channel certain programs to use one or the other?

Thanks a bunch!