Visualize two different pointclouds (PointCloud2) in separate views of rviz2

edit

In the end, I solved the problem. I used a launch file to open several instances of ROS2 and it works quite well, to be honest.

In order to have different instances you can have a launch file like this:

import os

from ament_index_python.packages import get_package_share_directory
from launch import LaunchDescription
from launch_ros.actions import Node

def generate_launch_description():
    config_camera_1 = "config_1.rviz"
    config_camera_2 = "config_2.rviz"
    config_lidar_1 = "config_3.rviz"
    config_lidar_2 = "config_4.rviz"
    config_lidar_3 = "config_5.rviz"

    print("SHARE_dir: ", get_package_share_directory('offline_sensor_data_server'))

    return LaunchDescription([
        Node(package='rviz2',
            executable='rviz2',
            name='rviz2_camera_1',
            arguments=['-d', config_camera_1],
            output='screen'
        ),
        Node(package='rviz2',
            executable='rviz2',
            name='rviz2_camera_2',
            arguments=['-d', config_camera_2],
            output='screen'
        ),
        Node(package='rviz2',
            executable='rviz2',
            name='rviz2_2',
            arguments=['-d', config_lidar_1],
            output='screen'
        ),
        Node(package='rviz2',
            executable='rviz2',
            name='rviz2_3',
            arguments=['-d', config_lidar_2],
            output='screen'
        ),
        Node(package='rviz2',
            executable='rviz2',
            name='rviz2_4',
            arguments=['-d', config_lidar_3],
            output='screen'
        ),
    ])

I hope it helps someone in the same situation.