If you want to drive both sets simultaneously (both active at once), you'll probably want to use the 1050's pre-amp outputs and a separate power amp to drive the second set while leaving the first set on the 1050's internal amp. I never tried that with the 1050, but it should work fine. If you want to be able to drive either set of speakers but not both at once, there are some good speaker selector boxes around that would let you choose speaker set "A" or speaker set "B".