Let me see if I understood your question.
Let's say I have 3 Powerpoint files open.
In the dock I will see the Powerpoint program icon with the "program running" indicator (your setting is for the little triangle).
If you hover your mouse over the Powerpoint icon, you will see three pop-up mini-windows appear - each one represents one of the open Powerpoint files. Each little window shows a "snapshot" of the application screen so you can get a better idea of which is which, and the window title is shown too.
To select the file you want, just click on it. You can also selectively close any instance by clicking on the red X.
Does that answer your question? BTW I am using the full version of ObjectDock - not sure if this feature is in the free version.