multiple video sources AR (ARToolKit or Vuforia)

i want to create AR in unity by using multiple inputs/sources at the same time. now using ARTOOLKIT but can switch to VUFORIA.

setup: - 4 webcam inputs going into unity. - in each webcam i have at least one or two tags visible - 3d objects are projected in each camera on their tags

question: how can i project on multiple webcam inputs into unity using ARTOOLKIT ?

so far: using ARToolKit should i capture all inputs, create it as one source and then send it to: AR Controller (Script)->Video options->Video config (something) ?

thanks for your attention