Do you have the Bose Soundtouch 10 or Acoustimass 10?
If you have the Soundtouch 10 then unless the Bose app can configure the speakers to work in stereo (the Sonos speakers and app do this) then you can't stream to them as stereo speakers only as two mono speakers. If you use the aux input you could connect each speaker to the left OR right output of the "controller" and select that input on both speakers.
If you have 2 Acoustimass 10 surround systems that you want to wire for both systems to work at the same time you would have to wire both subwoofers back to the "controller", what ever that is, for both systems to work together. Set the "controller" to 5.1 stereo (or something similar) in the surround sound mode of the "controller"