@chrismatheson Hello, currently that is not possible. There is a planned upgrade that will introduce Mastodon "lock down" that probably will offer that option. Announced here: https://www.patreon.com/posts/mastodon-2-9-and-28121681
Still, there is no ETA for that release or even if that will make it into production. Also, I am not fully aware of how the feature will work, only after that release I can give you a definitive answer.