Hi @keep_coding were you able to spawn and control multiple drones in the same session? I am trying to something similiar, I want to control the drones using pymavlink . I found a few old resources online
https://discuss.ardupilot.org/uploads/default/original/2X/d/d7083377f747deab79798e7a9cef58d433ff5f66.pdf
it is meant for gazebo-classic but with a few minor changes I was able to spawn the drones in Gazebo Harmonic.
But when i tried using the command in the instructions
sim_vehicle.py -v ArduCopter -f gazebo-iris --model JSON --map --console -I<instance no.>
I get a link down error, still trying to figure out the issue.