Unity Bluetooth Library for Android
The library let you control the Bluetooth capabablities of Android. It has a very simple API that gives you full control over multiple connections.
The library is available on Github, the library sourcecode.
The Asset actually contains two libraries. Both libraries could stand as two seperate Assets on the AssetStore. The one I recomened using is the BT library. The BT library provides all the needed features. The other library is just a simpler one (with less features) and a simple UI to configure its functionality.
Blog
I like to share Open Source projects, so check my Blog incase I already did.