[LAU] Mulitple sound caards with Jackd

I was reading here: http://bpmdj.yellowcouch.org/jack.html and became intrigued. A few questions. I would love to be able to run with (say) three ordinary USB2 audio-in ports plus my AudioTrak Prodigy HD2. 1. Can different jackd instances, connect and talk to each other? If I run four instances of Jackd and qjackctl under four different names, can I connect them all? 2. In the example at the web page linked above, an "ALSA multi" device is shown, combining multiple devices into one ALSA virtual device. If memory and CPU is not an issue, will doing this with one Jackd instance work better than four interconnected Jackd instances? It seems to me that this would require a "lowest common denominator" approach to latency-related settings, and combining PCI and USB strikes me as possibly troublesome because of the very different needs involved. J.E.B.