I don't know about the odb thing, but my iphone lets me have multiple Bluetooth devices connected simultaneously. For example, I use a fitbit, heart rate monitor and Bluetooth headphones/headset simultaneously while biking. You can only have one audio device active at a time though. But easy to switch between them.
Ordered JKUR X 11/25: Anvil - Dual Body Color Hard Tops - Auto - 4.10 - Side Airbags - A/C Temp Control - Remote Start. D 12/23, D1 1/6, Paint 1/20, 100% inspection 1/21, delivery 2/8, @Home 2/10!