MUC_NICKNAME generation for autoscaling Videobridges

I am planning to do a Managed Instanced Group in GCP for multiple Videobridges. The problem is that my saved image of my JVB retains its config everytime it spawns a new instance thus copying the MUC_NICKNAME of sip-communicator.properties. I tried this and it seems it won’t let me use the same MUC_NICKNAME for obvious reasons. So I tried commenting out this line hoping it would auto-generate on start but it seems there is a check before starting JVB and it won’t start without it. Is there any way to regenerate this with a command so that every instance will have a new MUC_NICKNAME? Or maybe it can fetch some ENV variable?