multiple key combinations for one command in compiz

I'm trying to change the default behavior of Super Right/Left arrow into that of Ctrl Super Right/Left arrow as well as CtrlAlt4/6.

Ctrl Super Right/Left arrow is used to change the position and size of the active window so it will only take up half the screen (this is called semi-maximization).

The normal approach to do this is to go to system setting -> Keyboard -> shortcuts -> windows and change the default shortcut into the desired shortcut, copy that shortcut and give it another key combination

This is a compiz thing (compiz grid) so you have to edit it in ccsm which is fine. Now the problem arises that you cannot set the same command to multiple shortcuts. So when I set this command to CtrlAlt4/6 (which I use when I have a lot of windows that need to be managed across multiple monitors) I cannot set it to Super Right/Left arrow (which I use on the go for quick window management).

How can I set a compiz command to multiple key-combinations?

Is it perhaps possible to set a key combination to press another combination?? like this:

Press Super Left Arrow --> send keys CtrlAlt4