Wow, I thought the 'code' tag would put in a scrollbar. Anyway, I pulled up the website and found the syntax for mouseclick just for fun:
<ClickMouse Button Stroke Target Mode Restore>

it looks like you can also manually enter the coordinates to click within a window. I'm not sure that it would be kosher with the Eula to have one button select the spell and then click each window say, at the characters' feet, but it could certainly be done with the help of a camera view macro. Making two separate macro buttons to do this ought to be perfectly justifiable anyhow.