Hide submenus when parent is active using CMenu widget

Is it possible to hide or prevent submenus from being displayed when the parent is active using the CMenu widget. I am using a horizontal menu structure -

Example:

Menu Link 1

  • Sub Menu Link 1

  • Sub Menu Link 2

  • Sub Menu Link 3

Menu Link 2

  • Sub Menu Link 1

  • Sub Menu Link 2

  • Sub Menu Link 3

Menu Link 3

  • Sub Menu Link 1

  • Sub Menu Link 2

  • Sub Menu Link 3

If Menu Link 2 is active, then do not show the Sub Menu Links.

I should state that I want to know how to do this (if possible) without extending zii.widgets.CMenu?