4 motor wiring

You'll have to remove (fold back) the red wires from each Esc, and you'll need three 'Y' leads, one for the pushers and one for the pullers and one to go to the receiver. It might be easier to make up a loom.
I'll post a schematic if you need one bloop.

Plug your receiver battery in to the receiver, as normal.
Take the first Y lead, and disconnect the red lead from the rx plug. Plug this into the throttle socket on the rx.
Take another two Y leads, plug them into the two ends you already have, so you now have four sockets.
Plug a speedo into each one.
Plug each speedo into a motor and a lipo as normal.

By disconnecting the red wire in the first Y lead, you have stopped the speedos from feeding the rx with volts, and fighting each other!
Normally you do not need to separate all the red leads, because it is just the same as having four batteries side by side, they won't fight each other.