Is possible open the same project on two instances of Intellij IDE

Just for new people who navigate here. You could just drag & drop the code you want outside android studio.

There is this topic about starting two instances of IntelliJ Start two instances of IntelliJ IDE

It is not possible with one instance from my experience

just open each one from different folder level.

For example: Project A has 2 folders (one inside another) and inside the 2nd folder there is code. Then open one instance from folder 1 and another instance from folder 2.

Open each instance by choosing open in new window..simple.

I found this really helpfull:

You can split the editor view vertically/horizontally, this will display the same file in both splits, then you can drag one of the tabs outside of the IDE to create a float editor window.

Another way to open multiple editors for the same file is to select the file in the Project view and press Shift+Enter.

Source: Serge Baranov response in this thread