web game invite code in link, redirect and read

I got a Html/CSS/JavaScript/Node.js/Socket.IO multiplayer online game. Domain: "multiplayergame.com" and I want invite someone with this link:

"multiplayergame.com/AB131" ---> "AB131" is the code for the party which the user is gonna join (by reading it from the url)

My problems:

1. how can I redirect "multiplayergame.com/AB131" to "multiplayergame.com" but the link in browser is still "multiplayergame.com/AB131". I read something about .htaccess? Is this the way to go, if so, how?

2. How can I edit the url in browser without redirecting/refreshing the page?

Sorry if my english is bad. Thanks for your answers.