Create two nodes with url aliases on one submission
Use hook_node_insert() where you can additionally create another node. I am not sure that the url alias will already be available.
If not use the following code, found at Programmatically create alias using pathauto for node, to get the original URL alias and then edit it to match your criteria:
module_load_include('inc', 'pathauto'); // include the inc file for Pathauto module

/*
pathauto_create_alias($module, $op, $source, $data, $type, $language)
@param $module: Your module name
@param $op: The operation (insert, update, return, bulkupdate)
@param $source: Internal Drupal path (i.e.: node/1)
@param $data: Addition data used to generate a pathalias, in this case the node object
@param $type: Type of content that will be used to match a pattern, defined in the backend url alias patterns
@param $language: If you have a multlingual website, you need to pass the language for which you want to generate the url alias
*/

pathauto_create_alias('your_module_name', 'insert', 'node/1', array('node' =&gt; $node), $node-&gt;type, $language-&gt;language); // Language is optional


Set the node alias and create a node with node_save().