FL-600R + FL-36R with my GH3?
I learned (and tested) by myself that GH3 can control several wireless flashes liked both mentioned above by using its own built-in flash light.
1.- You have to set the flashes to "remote controlled" using the mode button and make sure the sensor is looking at the camera, you can rotate and tilt the light wherever you want. You also set the comunication "channel" you are going tu use (1, 2, 3 or 4) and to which group belongs that specific flash unit (A, B or C).
2.- You have to set GH3 to wireless flash control using the menu's options, where you can set also all kind of variables for even 3 groups of flashes (A, B and C), which can iclude several flashes also (max of 3 is recomended per group though). Of course you have to pop-up the built-in flash to make all this work.
I hope this could help someone like me few ours ago.