Netty + ProtoBuffer: A few communication messages for one connection

While reading the Netty tutorial, I've found a simple description of how to integrate Netty and Google Protocol Buffers. I've started to investigate its example (because there is no more information in the documentation) and written a simple application like the example local time application. But this example is using static initialization in PipeFactory Class, e.g.:

import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelPipelineFactory;
import org.jboss.netty.handler.codec.protobuf.ProtobufDecoder;
import org.jboss.netty.handler.codec.protobuf.ProtobufEncoder;
import org.jboss.netty.handler.codec.protobuf.ProtobufVarint32FrameDecoder;
import org.jboss.netty.handler.codec.protobuf.ProtobufVarint32LengthFieldPrepender;

import static org.jboss.netty.channel.Channels.pipeline;

/**
 * @author sergiizagriichuk
 */
class ProtoCommunicationClientPipeFactory implements ChannelPipelineFactory {

    public ChannelPipeline getPipeline() throws Exception {
        ChannelPipeline p = pipeline();
        p.addLast("frameDecoder", new ProtobufVarint32FrameDecoder());
        p.addLast("protobufDecoder", new ProtobufDecoder(Communication.DataMessage.getDefaultInstance()));

        p.addLast("frameEncoder", new ProtobufVarint32LengthFieldPrepender());
        p.addLast("protobufEncoder", new ProtobufEncoder());

        p.addLast("handler", new ProtoCommunicationClientHandler());
        return p;
    }

}

(Please take a look at line p.addLast("protobufDecoder", new ProtobufDecoder(Communication.DataMessage.getDefaultInstance()));) and just one factory can be created (as I understand) for ClientBootstrap class, I mean bootstrap.setPipelineFactory() method. So, in this situation I c