Headphone Mixer?

I've been recording with linux for a couple years now, mostly with JAD, but I am planning on running 64Studio (3.0beta3) on a Dell laptop I am setting up. My recording setup is relatively simple, usually just recording single tracks at a time and building up my mix, only occasionally recording a group. But that is my problem. At times I want to record as many as six people singing together. My current setup has me hooking up two or three 3-way splitters with headphones (piggy-back style) out of my sound card's (M-Audio Delta 66 and/or Behringer UCA202 with a mixer) main output. An absolute mess. Especially because the signal gets really low by the time I have six headphones hooked up. I know there's a better way to do this, but I don't even know what the hardware I am looking for would be called. I searched a bit on a "headphone mixer", but all I found were little "personal headphone mixers", just 2 channel things. Anyone know what I am looking for?