Site magic usability

Hi!

I’m reading into site magic and have a couple questions that I’m hoping someone has tested out before.

I have 3 sites, and these sites move physically. Most times they’re all physically separated. On occasion they are physically together, and share the same internet wan connection and L3.

My question is when they are in this config, will the sites talk directly to each other on the local network, or will they require internet to maintain connection, and if there was no internet, but still had the sites on the same wan network. Would everything still function?

I do plan on testing this out, but wanted to ask in case someone already knows. Thanks!