This is great, thank you!
You can get access to most of them by setting them all to use the bridge network (network_mode: bridge). Then if you inspect the bridge network, you can see the bridge network ip’s of them all and use that for Heimdall. The Pi-Hole is an exception though since it requires a different network.
Maybe I just don’t know how… Do you have a compose script you could share?
I wonder who got fired after that.