Is it possible to connect three Fastrack switches to a manual control toggle? If so, can two have the green be thru and the third be out? I have a loop that connects to the main loop but has a switch that leads to a third loop -- so when switched to red two of the switches open to the loop but I want the third switch to go straight
Yes, but... The RSC Lights out under the turnouts (yellow) should only be connected from one turnout to the Controller. RSC outputs either +5 or -5VDC relative to GND depending on the turnout position. The Bi-color LEDs in the controller respond to this signal. If you try to connect multiple RSC outputs from turnouts with different positions, the signals interfere with each other and cancel and there's no LED illumination (it's probably not good for the output circuits either).
The Remote Controller toggle works by momentarily shorting ground to either the Out or Thru terminals which throws the points to the corresponding direction. For the two turnouts that operate in the same direction, wire the controller Red and Green to the Thru and Out Terminals in parallel to those as normal. Parallel the 3rd turnout with reversed connections to Out and Thru.
Assuming you have a solid Common Ground to all the Turnouts, you'd only need to wire the Controller ground (black) to one of the turnouts.