My bass player uses multiple bass guitars on stage and wants to have a foot switch that can turn on and off the outputs from his pickups. He has a 12 string bass with 3 outputs and two 4 string basses with single outputs. He runs them into 3 amps. Each of the 3 outputs from the 12 string would go to a seperate amp. The 4 strings would go to all 3 amps. Is there a product that he can buy or make with a box for his feet so he can turn off the 12 and then turn on his 4 string bass? Thanks in advance for any info on this.