<?php
function mergeIntersectingArrays($input) {
    $workArray = array_map(function ($e) {
        $r = new stdClass();
        $r->values = $e;
        $r->merged = false;
        $r->result = false;
        return $r;
    }, $input);

    for ($workKey = 0; $workKey < count($workArray); $workKey += 1) {
        $workElem = $workArray[$workKey];
        if ($workElem->merged) continue;
        for ($searchKey = 0; $searchKey < count($workArray); $searchKey += 1) {
            $searchElem = $workArray[$searchKey];
            if ($searchElem->merged || ($searchKey == $workKey)) continue;
            if (count(array_intersect($workElem->values, $searchElem->values)) > 0) {
                $workElem->values = array_unique(array_merge($workElem->values, $searchElem->values));
                $searchElem->merged = true;
            }
        }
        $workElem->result = true;
    }

    return array_values(
        array_map(function ($item) {
            return $item->values;
        }, array_filter($workArray, function ($item) {
            return $item->result && !$item->merged;
        })));
}