With a software like Hot Key Net or IS Boxer, ground target spells is quite easy.
All of the boxing software options have mouse broadcasting to one degree or another.

With some, you will press the hotkey for the spell.
Enable mouse broadcasting, with another hotkey.
Move the mouse to the desired location and click on the ground.
Disable mosue broadcasting, with a hotkey.

With others (like IS Boxer), you can tie the "Send Next Click" action to the hotkey that activates the spell.
You press whatever the keybind is, and it auto activates the mouse broadcasting for the target(s) (for everyone in the Action Target Group, you set in advance to broadcast the mouse on that keybind).
You see a mouse targeting circle in each of the others windows, which moves in real-time as you move the mouse in the main window.
Once you click, it disables the mouse broadcasting... and you're done.