Launch same node multiple times

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Hi,

I have a simple publisher which I want to launch with different parameters (rate and length) using the same code:

#include "ros/ros.h"
#include "std_msgs/String.h"

int main(int argc, char **argv)
{
    std::string NODE_NAME = "pc_pub_string";
    ros::init(argc, argv, NODE_NAME);
    ros::NodeHandle n;

    ros::Publisher string_pub = n.advertise<std_msgs::String>(NODE_NAME, 100);

    // Get the sample rate of this node (set in the launch file)
    ros::NodeHandle np("~");
    int loop_rate_p, data_length_p;
    if(np.getParam("loop_rate", loop_rate_p)){
        ROS_INFO("Initialized [%s] node at %d Hz", NODE_NAME.c_str(), loop_rate_p);
    }
    else{
        ROS_ERROR("Couldn't get rate parameter");
        return 0;
    }
    if(np.getParam("data_length", data_length_p)){
        ROS_INFO("Initialized [%s] node with %d elements in data", NODE_NAME.c_str(), data_length_p);
    }
    else{
        ROS_ERROR("Couldn't get data length parameter");
        return 0;
    }
    ros::Rate loop_rate(loop_rate_p);

    // Populate string message (content doesn't matter for proof of concept)
    std_msgs::String str;
    for(int i=0; i<data_length_p; i++)
        str.data.push_back(i);

    while(ros::ok())
    {
        string_pub.publish(str);
        ros::spinOnce();
        loop_rate.sleep();
    }


    return 0;
}

For this, I am using this launch file:

<launch>

  <group ns="publisher">
    <node pkg="proof_of_concept_string_ips" name="pc_pub_string0" type="pc_pub_string">
      <param name="loop_rate" type="int" value="2" />
      <param name="data_length" type="int" value="4" />
      <remap from="publisher/pc_pub_string" to="publisher/pc_pub_string0"/>
    </node>

    <node pkg="proof_of_concept_string_ips" name="pc_pub_string1" type="pc_pub_string">
      <param name="loop_rate" type="int" value="4" />
      <param name="data_length" type="int" value="2" />
      <remap from="publisher/pc_pub_string" to="publisher/pc_pub_string1"/>
    </node>    

  </group>

</launch>

The issue is that in the topic list, I only see what I wrote in NODE_NAME = "pc_pub_string". However, with ros info I can see that there are two publisher. I was hoping to have two topics, one called pc_pub_string0 and another pc_pub_string1. This could be achieved by having 2 .cpp files and compile 2 different executables, but their code would be the same.

Is it possible to avoid having two executables and use only one to manipulate their parameters (also topic names to have multiple) from the launch file?

Thanks for the help.