Other than using a time machine to go back to when cars were made to allow you to do that?
I’m giving you a hard time, no offense.
I don’t think these vehicles have an aux input like some (many?) vehicles used to. If you have the rear seat entertainment system and they have red/yellow/white inputs...then you could use those I think. (I don’t have the RSE so I’m not sure.)
One option would be to use an FM transmitter like this:
JETech Wireless FM Transmitter Radio Car Kit for Smart Phones Bundle with 3.5mm Audio Plug and Car Charger (Black)
https://www.amazon.com/dp/B00URUJWPW/ref=cm_sw_r_cp_tai_7wKkDbEYV3N4Z
I use this in mine as I bought $150 headrest DVD players for road trips instead of the $2k factory system. Plug that tansmitter into the headphone jack of the players, tune the dash radio to the selected fm station, and BOOM crystal clear audio from the DVD players through the sound system. No Bluetooth lag, no connection problems, no nothing.
Could be a good option to get audio from your CD player into the system.