Overlay duplication

In my application, there are two separate renderwindows displaying two separate scenes in a windows form.

Now, I want to render text on one window through the use of the OverlayManager, by using the TextManager class from the wiki. However, the text is rendered in both renderwindows! Is it possible to disable the Overlay for a renderwindow, or to let the OverlayManager singleton only draw to a specific renderwindow?

Thanks in advance.

Problem solved, answer can be found here.