Custom URL interception for my Wordpress plugin

I have my own Wordpress-plugin that is called via shortcode on the startpage of a website (not live yet). The plugin is displaying a map, displaying places as markers and calling places detail information via AJAX. That's all up and running. What I need is just a simple URL interception that should work like this: [login to view URL] must be rewritten internally (not visible to the end-user) to [login to view URL] while totally keeping the rest of the site (Wordpress) running. Any additional query-string-parameters like &lang etc. must be passed along too. You must adhere to WP-coding guidelines totally. I will then write an SQL-query to search for the place with that ID, so an if/else with a http 200 or 404 should also be included in your work. The condition for the if/else is not your task, so you can just do if(true){}else{} I can NOT send the contractor the plugin as it's highly confidential, but I think it's easy enough to just do the code-parts described here.