Okay... sorry for spamming the list, but I figured out a good solution. This is a cool CLI tip for those of you that don't know, but sorry if it is obvious to you.
Here are the steps for starting a detached screen session at startup for specific users to access later.
1.) Create a screenrc file containing two lines with "multiuser on" and "acladd $user,$user2" etc.
2.) Launch the server process (from within the init script) with "screen -c /path/to/your/screenrc -dmS yourscreenname yourprocess [yourprocessargs]"
3.) Take over as one of the designated users with "screen -rx processowner/screenname"