First of all, don't listen to anything Klondike bar says. He's just a troll and not a very bright one at that.

The simple answer to your question is that yes, you can hook as many grounds as you want to the metal frame. Unfortunately, what you are calling grounds are in fact the neutral wires on your sketch - so it's hard to tell exactly what the hell you want to do.

You seem to be on the right track with your thinking, but not with your drawing. Any fixture that has a green wire should also have a black and a white wire. Hook those to your power cord and hook all the greens together then out thru the power cord or hook the greens to the metal frame and the power cord green to the frame and you'll be good to go.

And you don't run lights in a series like that. You hook the lights up to the power cord - exactly the same way as if you were only going to hook up one light, except you've added a couple more fixtures.

PC :smokin: