Well if the windows are read-only then modifying their title attributes may be beyond the scope of normal UiPath capabilities. Usually each window of the same title comes with a window handle (hwnd) variable that is unique. But using that with lower level window functions may be too complex a fix.
Even if your window titles are identical, and you set up a loop with an Attach Window activity, it would latch on to the first instance of an identically named window. Closing that window would mean that each subsequent window would be detected on every iteration of the loop.
This process could be repeated until the Attach Window selector fails (in a try-catch loop) to mark the end of working through all the windows.
Alternately, an Advanced Selector with Regex may be used to look for the first instance of several untitled identical windows.
Both these approaches would not require you to modify the title of the window unless that is an absolute requirement of your automation process.