You are looking for a WordPress installation, thats not a Xampp issue and the problem is always the same, it does not matter if you have Xampp or Mamp or any Linux Distribution or whatever, it is a question of HOW to configure WordPress, so that multiple installations do not collide. You also could ask in a WIndows Forum, as Xampp runs on Windows and WordPress runs on Xampp, but thats also totally uselesse. You have to setup WordPress in a certain manner, and you have NOT to setup Xampp in a certain manner. Of course you may use Xampp as Webserver environment, but this not mandatory and it would of course also run on any other Webserver stack. The main problem is the configuration of WordPress. Not Xampp. Not Linux, Not Windows. WordPress. And this is NOT a WordPress forum.
Anyway, if i would have to do that, i simply would:
a) install each WordPress into its own folder, i.e. c:/xampp/htdocs/wp1 and c:/xampp/htdocs/wp2 and c:/xampp/htdocs/wp3.
b) apply different Databases for each WordPress installation, i.e. WP1, WP2, WP3 or similar.
Finally either install WordPress into
http://localhost/wp1 and
http://localhost/wp2 and
http://localhost/wp3. Or
http://192.168.x.xxx/wp1 and
http://192.168.x.xxx/wp2 and
http://192.168.x.xxx/wp3. Or
http://192.168.x.xxx/wordpress (in that case, simply create wordpress folder as you already did) and
http://192.168.x.xxx/wp1 and
http://192.168.x.xxx/wp2 or or or or or. You may also use VirtualHosts instead of plain IPs or whatever. Most important: use different foldes and different databases. Does not sound really difficult to me.
P.S.: Do NOT use the WordPress installer from Bitnami (maybe this is your concerne, you did not tell us about), download WordPress from the original WordPress site and follow the standard installation description of WordPress.