Is it permissible, in Sharia, for the heirs to agree that each group of them takes a specific plot of land to divide among themselves, knowing that the final division will be similar for all?

If every heir knows their share and portion of the inheritance, and the heirs agree to the division, there is no objection to that. This falls under the permissible reconciliation among Muslims, as long as it does not forbid what is lawful or permit what is unlawful. If the reconciliation is concluded with its conditions, everyone is obligated to abide by it. It is a condition for the permissibility of reconciliation that the heir be an adult and of sound judgment. As for a minor, an insane person, or a profligate, their reconciliation is not valid, and they must receive their full right. However, if the heir does not know the extent of their share of the lands and reconciles to the division, this reconciliation is not permissible due to the presence of ignorance therein.