Multiple pivot points using the bone tool?

How do you make multiple pivot points on a symbol using the bone tool? I would like make this 4-bar linkage hinge at all the pin joints, including the lower-left one (so it forms a closed loop that can collapse like a parallelogram). In the image below, it only pivots along the bone, and it won't let me link up the join in the bottom-left.

http://s1198.photobucket.com/user/Techn01d/media/FlashBoneTool1.jpg.html