Can you unlink your mastodon group (server) from the Federation?

Can you unlink your mastodon group (server) from the Federation?

I think Purism Social is its own independent mastodon instant not connected to the mastodon-federation. Is there something you can turn off during the installation of your own mastodon server installation to unlink? …to keep the server separate?

You might check LIMITED_FEDERATION_MODE on Configuring your environment - Mastodon documentation