Multiple Modeless forms, each with a Modal child form.

I have the need for the following scenario: I creat 2 or more Modeless child
forms from my main form. I can easily, as expected, switch betwenn them with
no problem. Each modeless child form must be able to create a single Modal
form. Due to the nature of the Modal form, I can't do this since once I've
created the first Modal form as a child of one of the Modeless forms, I
cannot switch focus to another of the Modeless forms inorder to create
another Modal form.

Briefly, here is the sequence of methods I want to use:

MainForm: Call Dialog.Show() multiple times creating a new ChildForm each
time.
ChildForm: Call Dialog.ShowDialog() once (but I want to be able to do this
in each ChildForm).

Any ideas?

Thanks in advance.