Is it Islamically permissible to allocate specific rows in the school prayer hall for each academic level, while prohibiting students of lower grades from filling empty spaces in rows designated for higher grades, and the Imam asks for the gaps to be filled, then students of order are asked to return to their rows if they advance?

It is obligatory to straighten the rows, complete them, and fill the gaps, as this is part of the perfection and establishment of the prayer. The Prophet, peace and blessings be upon him, commanded it and warned against neglecting it. The ruling on straightening the rows does not differ based on the place of prayer, whether it is in a mosque, a prayer hall, or elsewhere. If organizing the students can lead to the completion of the incomplete rows, with the front rows being filled first, then there is no objection. However, if this organization results in the first row not being completed because there are students from another class, then there is no concession for that, as it contradicts the Sunnah. The departure of students can be organized after the prayer ends to maintain order.