Kindly give me answers to these questions.
1. Can Muslims be buried in non-Muslim graveyards?
2. Can Non-Muslims be buried in Muslim graveyards?
3. Where do you bury a person who has a religion different from others and he has no graveyard of his own in Pakistan?
4. Can Qadianis/Bahais be buried in Muslim graveyards?
Islamic Shari'ah demands that Muslims bury their dead in graves. It is quite natural that when many Muslims are buried in a society, there is a need for a graveyard. That is how Muslim tradition of graveyards emerged, not that Muslims cannot be buried in places other than graveyards. We have many examples wherein Muslims were buried in places which never came in the general description of graveyards. The martyrs of Uhud for instance were buried in the plain of Uhud.
When Muslims bury their dead in graveyards, especially in societies where there are large Muslim populations, those places become exclusive graveyards for Muslims. It is a part of the Muslim tradition, not a part of, in my understanding, Islamic Shari'ah. When there is a matter which is a part of Muslim tradition and not the Shari'ah, it should be decided by the local law and customs. Therefore, one community can decide one thing and another can decide something different. However, that tradition cannot be declared a part of the Islamic law.
Muslims have been sensitive about not allowing non-Muslims to be buried in their graveyards in the Muslim majority societies, but they get their dead buried in the same graveyards as those of non-Muslims in the societies where they are living as minorities. Their sections are separated from others but the locality is a graveyard.
Thus the answer to your question is that while the Shari'ah does not specify anything definite about the Muslim exclusivity of graveyards, Muslim tradition has different versions of understanding on the question you have asked.