I'm glad to hear you're enjoying S+!
You sure can do what you're looking for, if you happen to know the exact X coordinate after which you want to be considered the right side, just change 1000 below to the X coordinate. Otherwise, use the first line of the script to find the X coordinate of the mouse location, then update 1000 to be wherever you want to switch from left to right processing
acMessageBox(acGetMouseLocationX(), "Mouse X", nil) --only use to find the X mouse coordinate, then remove
if acGetMouseLocationX() <= 1000 then
acMessageBox("Do left side stuff here","Left",nil)
acMessageBox("Do right side stuff here","Right",nil)