A full version app for Android, by Marek Masár.

Bluetooth Splitter Pro is a versatile and extremely easy-to-use tool for splitting a single Bluetooth stream into multiple streams. It works with Android devices running version 4.3 or higher. This app can also be used as a multiplexer to combine communication from slave devices to a single output stream to a master device.

This is very simple and easy to use. Just connect to paired devices and change the resending direction as needed. Take note, however, that some devices have trouble with multiple Bluetooth connections, so it would be best to get the trial version of this app first to check.