Hmm.... yes, that is possible, but not easy.
Plugins are DLLs that are mapped to the application's address space, so generally a plugin can do (almost) as much as every native part of the application.
Actually, implementing this as plugin would be as easy as pushing an event handler for idGoogle. That would intercept the event and let you do whatever you want when someone clicks that menu item.
However, the problem is that you don't know the value of idGoogle.
So, you would have to push an event handler for right-click, verify whether or not the control key is down, forward the event if it's not, and show your menu otherwise. Then you would have to listen to whatever event ID you assigned to your menu, and implement whatever should happen (copy the code from editorbase.cpp or whatever you want).