It's software dependent.
If the software supports logical inputs, like MAME, you can just program it to have Right=Right NOT Left, Left=Left NOT Right, and Front=Left AND Right.
Most of the commercial pinball applications don't support this though, so you'll need a circuit that will interpret the inputs for you.
I am attaching a diagram for a circuit that will do this, using (3) 5v DPDT Relays.
Without studying the current limitations, etc... on all the various encoders, I am reluctant to release any other ways of doing this.
The nice thing about this circuit is that it isolates the encoder terminals from the 5v source, and isn't USING the terminals to drive the relays.
You might have Randy, or Andy, suggest a different circuit, specific to their encoder, for accomplishing this.
I don't want to be responsible for a rash of warranty claims for either of them.