Excel 2013 How can I separate instances on the taskbar?

Hi, does anyone know how I can know which excel on my taskbar that are connected to the same instance?

Lets say I open two different instances of Excel 2013 (holding alt + opening a new instance/session of excel that runs separately).
Then I open for instance three workbooks in each instance/session. I will then have six windows open.

Is there a way to easily know which windows that are connected to the same instance? This is very important to me because I use macro-workbooks, and then sometimes I need to have them opened in same session, and sometimes I dont.. This is because they will either start automatic calculation, or they wont calculate at all.

I have the option "never combine" on the taskbar. And it didnt help to set it to "combine". Then all the six windows are combined to only one Excel-icon on the taskbar.

hope for help!!!