Can I access an MDI parent's menu from a modal dialog?

I'd like to access the menu on an MDI parent form from a modal window.  I don't think that's possible so I'm looking for options.  The requirements:

Open one or more MDI children from an MDI parent.  Based on actions taken in one of the MDI children, open another MDI child (let's call it ModalChild) of the same type.  Do not allow the user to interact with other MDI children until ModalChild is closed.  But do allow the user to use the MDI menu, same as the other children do.

If I use ShowDialog to open ModalChild, I can't use the menu.  If I disable the MDI parent, I can't use the menu. 

I'm coding in VB.NET 4.0.

Suggestions?

Thanks in advance.

mamacasc