For Joanneabarquez:
Try to use judicial settlement of the estate Rule 74 of the New Rules of Court. In this case, I think, repeat I think, palagay ko, ung 4 heirs can petition the court to partition the estate if the 2 don't want to settle the partition by extra-judicial settlement without the intervention of the court. Of course, you will be spending some litigation expenses. I don't know if the 4 can go ahead and make the extra-judicial settlement with provisions of the rights of those who have not participated in the settlement have 2 years to petition the court for their claim.
I am not a lawyer, but just an ordinary person and this is only a sort of comment/opinion...