Midi thru problems, rytm, keys

I’m trying to send midi from Ableton, through the keys or rytm into midi synths (Juno 106 roland and cs1x Yamaha). I can get the keys to receive and play the notes via USB midi in, but can’t get the midi message past the keys via thru into the Juno or Yamaha. Anyone experienced and/or solved a similar problem?

Someone correct me if I’m wrong but I believe that Thru works with an input coming into the instrument’s physical MIDI input first…and the Thru connection is just a duplicate of all that’s coming into the input…However, the USB-MIDI method is direct to the controlled instrument and only way to get more than that (to another instrument) is to set-up an internal sequence on the controlled instrument and trigger another connected via conventional MIDI cable…