Capturar una contenido entre string

$needle = '/<div class="list-group">(.+)<\/div>/s';

if ( preg_match($needle, $haysack, $matches) ) {
  $between = $matches[1];
}

Capturar todos las coincidencias

$needle = '/<a href="(.+)" class=".+" title="(.+)" style/';

if ( preg_match_all($needle, $haysack, $matches, PREG_SET_ORDER) ) {
  foreach ( $matches as $m ) {
    $href = $m[1];
    $title= $m[2];
  }
}