I'm not sure exactly what you're asking, but I believe the answer is yes, you can run both outputs to one amp. *These guitars have two outputs, A and B. *There is a toggle switch to select between magnetic and piezo output, and there is a push button switch. *When the push-button switch is in one position, the magnetic output comes out of Output A, and the piezo output will come out of Output B. *With the push-button switch in the other position, both outputs will come out of Output A. *However, you can only select magnetic OR piezo, not both at once.
So I think your answer is yes. *If the push-button is pressed in, you can use one cable from one output running to one amp, and then use the mini-toggle to select magnetic or piezo output to the amp. *Hope that answers your question.
I will add though, that the piezo sounds a lot better running through a separate acoustic amp, especially since it has no EQ of its own.