Hello all!
I have a Nord Electro 5D and a Nord Lead 4 set in a two tier configuration for live gigs.

I am pretty new thus unknowledgeable regarding MIDI and trying to achieve the following:

Scenario A:
Sometimes when I play the Nord Lead I need ONLY the Electro to respond
eg- I'm onstage playing Piano on Electro with B3 Hammond up on the Nord Lead (the Nord Lead needs to generate NO sound of it's own at this stage).

Scenario B:
Other times when I play the Nord Electro and the Nord Lead together I need to ONLY hear the sounds of each unit's OWN sound without hearing the other.
eg- I'm onstage playing Piano on the Electro and Arpeggiator/LFO sweeps on the Nord Lead.

ALSO in this same scenario, when I'm playing each unit together, then when I select a program on the Nord Electro I want it to automatically select a corresponding program on the Nord Lead so I don't have to remember to switch the Nord Lead program knob as well - I want to be able to change BOTH with just a flick of the Electro program knob.

My problems are:
When I set the MIDI Global to 16 on the Electro and to 2 on the Lead (see config list below), then the Electro sounds are sounding on the Lead via MIDI (which is good)
BUT - - how do I shut the sound of the Nord Lead up at this stage as I can still hear it's sounds as well - or do I have to just turn the volume on the Lead to zero? Or is there another way?
In this configuration the program changes won't send from the Electro to the Lead.

My other issue is when I change the MIDI Global on the Lead back to 16 then the program changes work fine as in Scenario B but then I am hearing BOTH sounds of BOTH units on each keyboard.

Thanks to anyone in advance who may be able to help me out, I imagine to someone who knows their stuff it may be a simple answer.

My setup is:

I have 2 MIDI DIN cables each from the MIDI IN of each unit to the MIDI OUT of the other.

On the Electro I have MIDI set as follows -
Local Control Mode: ON
Channel Global: 16
Channel Lower Receive: OFF
Channel Upper Receive: OFF
Channel Upper Split: 2
Control Change Mode: SEND/RECEIVE
Program Change Mode: SEND
Transpose MIDI at: MIDI IN

On the Nord Lead I have set as follows -
Channel Global: 2
A, B, C, D Slot Channels: All set to OFF
Soft Thru Channel: OFF
MIDI Interface: PU (PIN & USB)
Local Control Mode: On
Control Change Mode: OFF
Control Change Mode: SEND & RECEIVE
Program Change Mode: RECEIVE
Pitch bend Mode: SEND & RECEIVE