In Qt3, I guess the only way to create transparent widgets is to perform masking on the widget itself. However what is the best way to handle in the following scenario?

Take for a example that I have a map as my parent widget.
I would like to display text or small pixmap as widgets on top of the map. These widgets must be transparent(ie. I must still be able to see parts of the map beneath the widgets) and these widgets may be created or destroyed at random. The quantity of these widgets is also not known beforehand.

What is the best approach to handle the above scenario? Is masking still the way to go, esp when the small of these widgets are not known?