Dudley,
I replaced the battery in the A unit with a BCR. Old batteries are now ‘throw away’ batteries.
So, I have a powered A unit, a powered B unit, another powered B unit and a dummy A unit. All of them are connected with cables so having all 3 powered units in the OFF position will do what I intend to do with N,R,N,F sequence. The 2 B units do what the lead unit will do.
Thank you for responding with something I thought was the way it would work, just needed a 2nd opinion. Thanks!