Rotate objects with reference

I am building a railing along a curve, where the number of posts are undecided. The railing has glass panel infill between the posts, changing is size and orientation as the number of posts is increased or decreased.

The glass is mounted onto a hinged mount that is located on each post.

I have created a file that allows me to space any number of posts evenly along the curve, however I can’t figure out how to get the hinged mount to rotate so they will line up with the opposing one.

I made the geometry and I got it to flow along a curve in 3 groups [1 is the fixed post and the other 2 are the moving hinges that hold the glass]

I think I can get the angle the hinge needs to rotate the hinge from a line that runs from on posts center to the next posts center.

I did this by flattening one set of points and running a line from on point to another. I cant seem to figure out how to sort the lines/points. Or if there is another way I could do it all together. I have included my file and a picture of what i am trying to explain.

Any help would be great! thanks.