Hey krizzz,

I used the following solution.
Build a fibaro dimmer 2 with a double switch in the wall.
Connected both switch cables, then build another dimmer 2 INTO the second lamp, and can control both dimmers from one place.

That did the trick for me, success.

I also use both z-wave and RFX as well.
The kaku switches and dimmers for building behind the traditional switch are working fine.

Z-wave for controlling the lights is way too expensive, and has no advantages.

Success