How to make wire that transmit on all directions?

How do I make a wire block that transmit power to every adjacent wire, except the wire block it received from?

So it will look at all the wires in all directions, if there's a wire, check if that wire block gave it the power it transmitting, if not send power there.

I know how to do most of it, but I don't know how check which adjacent wire block was the source of the power.

Can someone help?