You can change wall template file path for specific type (like group , user, businesspage). We will cover a group type in this example.

You may look following in OssnWall component

~~~
ossn_add_hook('wall:template', 'user', 'ossn_wall_templates');
ossn_add_hook('wall:template', 'group', 'ossn_wall_templates');
~~~

Example
~~~
<?php
function my_component_init(){
ossn_add_hook('wall:template', 'group', 'my_component_hook');
}
function my_component_hook($hook, $type, $return = null, $params){
ossn_trigger_callback('wall', 'load:item', $params);
$params = ossn_call_hook('wall', 'templates:item', $params, $params);
//path of the file
return ossn_plugin_view("wall/templates/wall/group/item", $params);
}
ossn_register_callback('ossn', 'init', 'my_component_init');
~~~