i asked rf tech support heres my question
"i need to hook up all 3 100.4s to the 360 for my 3 way active system. can it be done. heres a diagram"
there answer
Thanks for contacting us. Yes, that would indeed work. A couple quick notes.....You won't have fader control, including myself not many people care about that anyway. For the 3Sixty to work it needs to have at least a Left and Right connected to the Front inputs, the unit will automatically give you a summed output on the center and sub if no input is present.
what does this mean? "the unit will automatically give you a summed output on the center and sub if no input is present."