Try http://bridge.sourceforge.net/howto.html for more details on bridging.
This solution would absolutely work for me. I'd have to have the Bridge machine itself participating in the network, but the 'howto' tells how to do that.
In an ideal world, I would like to inhibit traffic from the fast machines being bridged onto the slow machines' part of the network unless it is actually directed to them so as to maximise the bandwidth on that part of the network, but I can live without that feature.
Does that sound right now ?
Yes; the Linux bridge acts as a switch, so you'll get your desired behaviour of keeping the "fast" traffic off the "slow" network without even trying :-)
See http://www.linux.com/howtos/BRIDGE-STP-HOWTO/what-is-a-bridge.shtml
Paul.
