Here’s what I want to do:

If I use startActivity I start a new Activity and I can’t use StartActivityForResult from Main Menu -> Total. I would like to go back on the Main Menu activity already present in my stack and remove Activities A, B ,C and Total.
Have you tried using
FLAG_ACTIVITY_CLEAR_TOPflag in your intent (used to start “Main Menu” from “Total”)?http://developer.android.com/reference/android/content/Intent.html#FLAG_ACTIVITY_CLEAR_TOP
If set, and the activity being launched is already running in the current task, then instead of launching a new instance of that activity, all of the other activities on top of it will be closed and this Intent will be delivered to the (now on top) old activity as a new Intent.