Buddypress - Change Groups slug

change_buddypress_groups_slug.php

// add this code to functions.php  
// then edit groups page from wpadmin pages ( change permalink slug to "your_new_slug_for_groups" ) and  save!
add_filter('bp_get_groups_root_slug', 'bp_change_groups_root_slug');
function bp_change_groups_root_slug( $group ){
	return "your_new_slug_for_groups"; //For example "gatherings"
}