Callback function in menu items field Is it possible to put callback function here $items['callback?'] ? I need to change this field every time when user make some changes. The biggest problem for me is that hook_menu() is cached and menu is rarely updating.
Technically, you can use a function to return an array of menu router items but practically it will not work because of caching. 

However you can register wildcats paths like companies/so your page callback will be fired on every companies/ pages. 

To do so, set the key of the $items like this:

$items['companies/%'] = array(...menu router info here ...);