How to connect SS823 to redundant power supplies as the SS823 has only one input?

Configuration of redundant AC 800M HI and redundant power suplies:

- On red. CPU level we included 2pcs of SS823 voting device and 2pcs of SD831 power supply (1pc of SS823 because it´s safety and 1pc for redundancy of power supplies)

- On S800 I/O level we included 1pc of SS823 voting device and 2pcs of SD832 power supply(for redundancy of power supplies)

Customer tells that he can´t use SS823 voting device for redundancy of power supplies, as the SS823 has only one input and he´d like to use SS832 instead. I think that we must use SS823, simply because it´s safety.

And here comes the question:

How to connect SS823 to redundant power supplies as the SS823 has only one input?