Adobe flash media server 4.5 streaming to multiple RTMP

First when you need something you need to learn and avoid to ask to someone else to do the job for you, so

AMS server-side ActionScript language reference

There are many ways to do it, and there are examples if you search on internet.

for example, when you publish from Media Encoder to your server app, on the main.asc

you can create an automatic stream dispatching as soon as it's published, like

applications.onPublish = function(client,stream){

     var nc = new NetConnection();

     nc.onResult = function(info){

          ....   

     }

     nc.onStatus = function(info){

          if(info.code == "NetConnection.Connect.Success"){

               var ns = new NetStream(nc);

               ns.attach(stream);

               ns.publish("whatever_name or stream.name");

          }

     }

     nc.connect("rtmp://xxxx.xxxx.xxxx/xx/xx");

}