BuddyPress.org

== Is’it possible to do that or have I to install a new WP instance with BP some where else ==

I always think it’s more secure to install a new and separate instance of WP/BP elsewhere. You could install the multinetwork plugin https://wordpress.org/extend/plugins/wp-multi-network/ where BP installation in one network won’t show up in the other networks …. though this method is overkill for one BP install.