@godarklight: Thanks for the information. I've figured out how sharing vessels works currently and it is perfect for the server my brother and I are playing on. One thing I did notice last night was that the asteroids on our server keep resetting every time I log on. I logged into the server, tracked a bunch of asteroids (even renamed a couple), and then logged off. The next time I logged back in all of the asteroids I had tracked were gone and a new batch of asteroids were spawned. Is there any way to make the asteroids persistent between logins? It's not much fun to have the Class E asteroid on an impact trajectory with Kerbin disappear every time I log off.