thanks for the reply.

re:
1) i was only thinking about CV/automated function, i didn't account for manual control.

2) make i can explain better:
if Switch1 is Master and Switch2 is slave, Can the Master be used as 2 sources-> 1 Destination while the Slave is used 1Source -> 2 Destinations switched synced to the Master  e.g. while Master = Source1 to Destination, Slave=Source to Destination1 and  while Master=Source2 to Destination, Slave=Source to Destination2. 

In short, is a Slave's signal flow direction (not state) independent of the Master and other Slaves or is the signal flow direction of a slave restricted to match its master

3) the description makes it appear as you much hold the manual button down.  Can this be a push (not hold) to switch state instead