There are 4 ports. So you can connect 4 Shifty or 4 BIT to the hub.

Once the Blak Bullet is connected to the system, you will see a popup message for each button that is pressed. It tells you which port number it is.

If you want to attach multiple buttons to same port, that will take a little DIY. In the future we will have a ready made solution for this.

The system works based on voltage level. So you need to connect the wires together (preferably soldered). 

Put a resistor in series with the buttons to identify the port:

A - no resistor
A-1 1k
A-2 2.2k
A-3 2.7k
A-4 3.6k
A-5 4.3k

Same for B, C, D ports

You can adjust the level with the Button Tuning screen if its not quite correct.