I think I got it!

I ended up trying a few things to get strange results then settled on this.

I enabled multi tenant.
I put Auto Attendant 2 in auto mode and recorded a greeting. During the day it forwards to our desk phones. At night, I recorded an empty greeting and it forwards to our oncall phone.

The oncall phone has 3 buttons setup that forward to 1 of 3 guest info boxes that play a message then forward to a GoTo that sends the call to a cell phone.

It seems kind of messy to send the call around so much but that's how it was setup before. (Guest info to GoTo)