Why not just copy across the blockchain and then you don't need to use your internal network to download anything.
I was going to suggest using ftp if it is a multi-user network, but jackg beat me to it. I use an external SSD to move nodes between computers.
I'm thinking ot trying to use a remote blockchain as the base for a new pruned node, and I hoped that this would avoid the need to download the whole chain. Is there a way to do this?