Backstack with multiple Fragments per layout

I want to create stack of multiple fragments included in linear layout. To put set of fragments to activty I use following code (R.id.content is LinearLayout):

priv开发者_C百科ate void pushToBackStack(final Fragment... fragments) {
    final FragmentManager fm = getSupportFragmentManager();

    final FragmentTransaction ft = fm.beginTransaction();

    for (int i = 0; i < fragments.length; i++) {

        if (i == 0) {
            ft.replace(R.id.content, fragments[i]);
        } else {
            ft.add(R.id.content, fragments[i]);
        }
    }
    ft.addToBackStack(null);
    ft.commit();
}

when i call

pushToBackStack(f1, f2);
pushToBackStack(f3, f4);
pushToBackStack(f5, f6);

there're f3,f5 and f6 visible on screen, and after pressing Back button f2,f3,f4 are displayed.

Expected behaviour is f5,f6 -> Back -> f3,f4 -> Back-> f1, f2

You can't chain calls that way, you would need to call a commit per replace or add