Multiple Bluetooth devices at same time

That depends. You can use multiple Bluetooth devices if they're using different profiles. For example, you can use an Apple Watch and Bluetooth speakers at the same time. What you can't (generally) is use two devices that use the same profile at the same time, e.g. two speakers.

Perhaps if you provided a few details and explained exactly what it is you're trying to do, people could offer more advice.

Sorry. One at a time only.