This is not a pattern that is possible in OOP. Also, can.extend just merges Objects together and is not intended to be used with Classes (Construct, Control, Observe, etc).
What your saying when you ask to extend 3 Controls is you want to combine the functionality of 3 different Controls into one?
If the 3 Widgets each do something unique then you could have ModuleController create an instance of each and then do some other stuff.
If you explained what you are doing in more concrete terms, we could find a pattern that works.