Disabling auto-download for specific addons on server

I’m helping my friend out with a new server he set up. I showed him how to load up WAC helicopters on the server, but we don’t want to lose traffic from the long download the helis take if someone doesn’t have them. I recall there being a lua file one could delete to disable the auto-download for the addons, but I cannot remember for the life of me. Anybody know?