Default Bluetooth and Auxiliary Audio at the same time?

Ok, so on my other phones I could have my Bluetooth connected, be playing music through an auxiliary cable to my truck speakers, when I get a call, switch audio to my Bluetooth.
On my S5, it doesn't give me the option to switch, the audio just stays on the truck speakers.
Is there any way to change this to have it play music through speakers, but phone calls through Bluetooth?