The HttpRequestPool class provides a solution. Many thanks to those who pointed this out.
A brief tutorial can be found at: http://www.phptutorial.i
A friend pointed me to CurlObjects ( http://trac.curlobjects.com/trac ) recently, which I found quite useful for using curl_multi.
$curlbase = new CurlBase;
$curlbase->defaultOptions[ CURLOPT_TIMEOUT ] = 30;
$curlbase->add( new HttpPost($url, array('name'=> 'value', 'a' => 'b')));
$curlbase->add( new HttpPost($url2, array('name'=> 'value', 'a' => 'b')));
$curlbase->add( new HttpPost($url3, array('name'=> 'value', 'a' => 'b')));
$curlbase->perform();
foreach($curlbase->requests as $request) { ... }