AutoCad :: Create Vertical Lines From Point Reference

I am working on a horizontal directional drill with multiple survey points.

The survey points make up (what looks like an upside down dome) and they are all connected with polylines. I need to add straight vertical lines to each point. Of course I can do this manually, but I'm wondering if there's a way to automate it. I've tried Lee's point manager, but it seems the problem is there's no option for xstart, xend, and ystart, yend. I also tried created a block out of a line then importing that on the points with point manager, but I need all of the lines to end at the same position at the top. This doesnt work because as you can see the points aren't all equal from the bottom. I also cannot find a way to trim blocks. I was hoping blocks would have the same xstart and xend, etc. as a line, but they don't.