BuddyPress works like a central community, so it’s either you have one BuddyPress website or not.
What you can do is to install it on a single subdomain.
then you would have to edit your wp-config.php file, add the following line
define ( ‘BP_ROOT_BLOG’, 3 );
the number 3 is your blog id.
I’ve found the solution from
Thanks to Sabuntu!
I’m requesting the subdomain installation as a feature though.