Well, sort of...
It sounds as if you want to use the Streamers as a cluster of extra conventional servers. They will need to allow conventional serving, and set a bandwidth % that allows at least one outgoing conventional stream (sorry the bandwidth use config is a bit of a mess). But you will still need a main broadcasting Streamer to feed the p2p stream to them, and to serve the .pls file that contains their IPs. This .pls will not include your main icecast server though, so you will effectively have two conventional streams: the icecast one, and the streamer cluster one. You could dump the icecast server and use the broadcast Streamer as the main conventional server, which would then have all the available conventional servers in one .pls served by Streamer.
This is all a bit complicated, and not what was really intended with conventional serving. It would be simpler just to have 2 listening links: one for the icecast server for your 'bush voting'
users who can't manage to install things, and one for your more able 'kerry voting' users who can install Streamer, and just use streamer in normal p2p mode.