$output = "";
if ($modx ->user ->isMember('Usergroup')){
$output = $modx->getChunk('Chunk to display');
}
else if ($modx ->user ->isMember('anonymous')){
$output = $modx->getChunk('Display different chunk');
return $output;[[[[+modx.user.id:ismember=`yourUserGroup`:then=`!$chunkA`:else=`!$chunkB`]]]]