$rs_Section = CIBlockSection::GetList(
	array('DEPTH_LEVEL' => 'desc'),
	$ar_Filter,
	false,
	array('ID', 'NAME', 'IBLOCK_SECTION_ID', 'DEPTH_LEVEL', 'SORT')
);
$ar_SectionList = array();
$ar_DepthLavel = array();
while($ar_Section = $rs_Section->GetNext(true, false))
{
	$ar_SectionList[$ar_Section['ID']] = $ar_Section;
	$ar_DepthLavel[] = $ar_Section['DEPTH_LEVEL'];
}

$ar_DepthLavelResult = array_unique($ar_DepthLavel);
rsort($ar_DepthLavelResult);

$i_MaxDepthLevel = $ar_DepthLavelResult[0];

for( $i = $i_MaxDepthLevel; $i > 1; $i-- )
{
	foreach ( $ar_SectionList as $i_SectionID => $ar_Value )
	{
		if( $ar_Value['DEPTH_LEVEL'] == $i )
		{
			$ar_SectionList[$ar_Value['IBLOCK_SECTION_ID']]['SUB_SECTION'][] = $ar_Value;
			unset( $ar_SectionList[$i_SectionID] );
		}
	}
}

function __sectionSort($a, $b)
{
	if ($a['SORT'] == $b['SORT']) {
		return 0;
	}
	return ($a['SORT'] < $b['SORT']) ? -1 : 1;
}

usort($ar_SectionList, "__sectionSort");