G.O. Can't handle this, but pen sets can:
http://blog.graphisoftus.com/archicad-education/tips-and-tricks/pen-sets-part-eight-thoughts-on-nami...
If you haven't already, download my template (
http://www.shoegnome.com/template/ ) and look at it. I have 2 pen sets: one has hatches on and one has hatches off. To turn hatches off I change the color of the foreground fill to match the background fill. I use colored fills, but if you don't like colors, you could do this by having a gray foreground and white background pen in the ON pen set, and then switch both to white in the OFF pen set. I also have one foreground pen that always stays ON because some hatches you always want on while others you want to turn on and off.
In the image below the bottom two rows are my hatch pens. The lower one is always colored. The one above switches between gray and matching the color below it (thus turning the hatches on or off)