A/B switch

[WesMVaughan]

How could I wire an A/B switch to where I could send my guitar signal to two different amps and have two foot switches that can either activate A,B or A&B?

[petemoore]

  Suggestions:
  Buffered split, then through a couple of to-ground-switches [one for each output, which cancel [or not] A and/or B output.
  Lifting the ground to the amps via ~expensive audio transformers might help hum, the 'large current' grounding of 2 amplifiers may cause a voltage between the amplifier grounds to = hum, with my amps I only get a very little hum increase, but it would be nice if the amps have independant input grounds.