2 bluetooth devices

[Windows Central Question]

i drive a semi and use a plantronics headset for phonecalls i want to use a ue boom bluetooth speaker for audiobooks. on android i could go into each device and choose what i wanted each to do on the headset i could choose for it to only do phonecalls and the speaker only for music. i have tried everything i can think of to do this on my lumia 950 but nothing works. i cant even connect both at the same time does anyone have any ideas that i might not be thinking of