Connecting lines problem

["lesliek ozemail com au" <lesliek ozemail com au>]

I'm trying to create a simple diagram, which will probably be my sole effort in
the field.

I've created an object joined by a vertical line to a horizontal line beneath it.
Beneath the horizontal line are five more objects, each of which I want to
connect to the horizontal line by a vertical line.

My problem is that the connection points available to me on the horizontal line
and on some of the objects beneath it mean that any line between them will not be
straight up and down, but at an angle.

The point's a small one, but I'd like my connecting lines all to be straight up
and down.

Is there a way to manipulate the connection points on the horizontal line and the
objects so that they're on my grid lines or, at least, will produce straight up
and down connecting lines?
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