(Note: Since the question language isnt clear; it just seems to me the
1. The purple-blue "Wall" (technically the plurae; containing plural space not shown) is being refered as the bag.
2. The ruptures are drawing artefacts. There arenot such ruptures.
3. I assume you know that the lumen of the broncheoles is continuous with the lumen of the alveoli ("grapes" in your analogy).
I would request you to clarify the language of the question.)
"So how by creating partial vacuum inside lungs themselves (like in bags) makes air come into alveoli"
Up to best of my understanding; atmospheric air has its own pressure, and own ability to expand. So when chest muscles expand and let the lungs to expand (probably you refer it with analogy of "bag") gives space to the alveoli to expand, the atmospheric air shall come through the broncheole and fill the alveoli to expand them until and unless a certain equilibrium appear.
The "bag" you mentioned (Purple-blue mark?) isnt like an empty bag; it can transfer the pressure to alveolar wall. Because the "bag" is filled with compact alveolar wall (imagine your "bag" (blue) as a ruber balloon and remaining lung tissue as a mass of sponge tightly filled in that baloon) and there are some tissue fluids too. so an improvised analogy would be like this:
Note the springs i have drawn are not real spring. I hypothetically drawn to mean the wall is able to rtansfer the push and pull to alveoli.
The realistic histological section will help to clear some confusion I hope.
So does bronchi have some kind of openings in them to let pressure
inside "bags" connect to outside
If there were rupture in bronchi or alveoli; then opposite is expected. it should leak the air to freely move to the "bag" you said, and would destroy the way to develop pressure difference and will cover up the alveoli and will crumble them (imagine the video that user @John has shared; if the red balloon is ruptured, you will be no more be able to inflate the baloon the way they are inflating.